Implemented TactilityKernel and DevicetreeCompiler, updated licenses & copyrights (#452)

**New features**

- Created a devicetree DTS and YAML parser in Python
- Created new modules:
  - TactilityKernel (LGPL v3.0 license)
  - Platforms/PlatformEsp32 (LGPL v3.0 license) 
  - Platforms/PlatformPosix (LGPL v3.0 license)
  - Tests/TactilityKernelTests

Most boards have a placeholder DTS file, while T-Lora Pager has a few devices attached.

**Licenses**

Clarified licenses and copyrights better.

- Add explanation about the intent behind them.
- Added explanation about licenses for past and future subprojects
- Added more details explanations with regards to the logo usage
- Copied licenses to subprojects to make it more explicit

TactilityKernel/Include/Tactility/drivers/Gpio.h

@@ -0,0 +1,90 @@
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <Tactility/Device.h>
+
+#define GPIO_OPTIONS_MASK 0x1f
+
+#define GPIO_ACTIVE_HIGH (0 << 0)
+#define GPIO_ACTIVE_LOW (1 << 0)
+
+#define GPIO_DIRECTION_INPUT (1 << 1)
+#define GPIO_DIRECTION_OUTPUT (1 << 2)
+#define GPIO_DIRECTION_INPUT_OUTPUT (GPIO_DIRECTION_INPUT | GPIO_DIRECTION_OUTPUT)
+
+#define GPIO_PULL_UP (0 << 3)
+#define GPIO_PULL_DOWN (1 << 4)
+
+#define GPIO_INTERRUPT_BITMASK (0b111 << 5) // 3 bits to hold the values [0, 5]
+#define GPIO_INTERRUPT_FROM_OPTIONS(options) (gpio_int_type_t)((options & GPIO_INTERRUPT_BITMASK) >> 5)
+#define GPIO_INTERRUPT_TO_OPTIONS(options, interrupt) (options | (interrupt << 5))
+
+typedef enum {
+    GPIO_INTERRUPT_DISABLE = 0,
+    GPIO_INTERRUPT_POS_EDGE = 1,
+    GPIO_INTERRUPT_NEG_EDGE = 2,
+    GPIO_INTERRUPT_ANY_EDGE = 3,
+    GPIO_INTERRUPT_LOW_LEVEL = 4,
+    GPIO_INTERRUPT_HIGH_LEVEL = 5,
+    GPIO__MAX,
+} GpioInterruptType;
+
+/**
+ * @brief Provides a type to hold a GPIO pin index.
+ *
+ * This reduced-size type is sufficient to record a pin number,
+ * e.g. from a devicetree GPIOS property.
+ */
+typedef uint8_t gpio_pin_t;
+
+/**
+ * @brief Identifies a set of pins associated with a port.
+ *
+ * The pin with index n is present in the set if and only if the bit
+ * identified by (1U << n) is set.
+ */
+typedef uint32_t gpio_pinset_t;
+
+/**
+ * @brief Provides a type to hold GPIO devicetree flags.
+ *
+ * All GPIO flags that can be expressed in devicetree fit in the low 16
+ * bits of the full flags field, so use a reduced-size type to record
+ * that part of a GPIOS property.
+ *
+ * The lower 8 bits are used for standard flags. The upper 8 bits are reserved
+ * for SoC specific flags.
+ */
+typedef uint16_t gpio_flags_t;
+
+/**
+ * @brief Container for GPIO pin information specified in dts files
+ *
+ * This type contains a pointer to a GPIO device, pin identifier for a pin
+ * controlled by that device, and the subset of pin configuration
+ * flags which may be given in devicetree.
+ */
+struct GpioPinConfig {
+    /** GPIO device controlling the pin */
+    const struct Device* port;
+    /** The pin's number on the device */
+    gpio_pin_t pin;
+    /** The pin's configuration flags as specified in devicetree */
+    gpio_flags_t dt_flags;
+};
+
+/**
+ * Check if the pin is ready to be used.
+ * @param pin_config the specifications of the pin
+ * @return true if the pin is ready to be used
+ */
+static inline bool gpio_is_ready(const struct GpioPinConfig* pin_config) {
+    return device_is_ready(pin_config->port);
+}
+
+#ifdef __cplusplus
+}
+#endif

TactilityKernel/Include/Tactility/drivers/GpioController.h

@@ -0,0 +1,28 @@
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "Gpio.h"
+#include <stdbool.h>
+
+struct GpioControllerApi {
+    bool (*set_level)(struct Device* device, gpio_pin_t pin, bool high);
+    bool (*get_level)(struct Device* device, gpio_pin_t pin, bool* high);
+    bool (*set_options)(struct Device* device, gpio_pin_t pin, gpio_flags_t options);
+    bool (*get_options)(struct Device* device, gpio_pin_t pin, gpio_flags_t* options);
+};
+
+bool gpio_controller_set_level(struct Device* device, gpio_pin_t pin, bool high);
+bool gpio_controller_get_level(struct Device* device, gpio_pin_t pin, bool* high);
+bool gpio_controller_set_options(struct Device* device, gpio_pin_t pin, gpio_flags_t options);
+bool gpio_controller_get_options(struct Device* device, gpio_pin_t pin, gpio_flags_t* options);
+
+inline bool gpio_set_options_config(struct Device* device, struct GpioPinConfig* config) {
+    return gpio_controller_set_options(device, config->pin, config->dt_flags);
+}
+
+#ifdef __cplusplus
+}
+#endif

TactilityKernel/Include/Tactility/drivers/I2cController.h

@@ -0,0 +1,28 @@
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "Gpio.h"
+#include <Tactility/FreeRTOS/FreeRTOS.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+struct I2cControllerApi {
+    bool (*read)(struct Device* device, uint8_t address, uint8_t* data, size_t dataSize, TickType_t timeout);
+    bool (*write)(struct Device* device, uint8_t address, const uint8_t* data, uint16_t dataSize, TickType_t timeout);
+    bool (*write_read)(struct Device* device, uint8_t address, const uint8_t* write_data, size_t write_data_size, uint8_t* read_data, size_t read_data_size, TickType_t timeout);
+};
+
+bool i2c_controller_read(struct Device* device, uint8_t address, uint8_t* data, size_t dataSize, TickType_t timeout);
+
+bool i2c_controller_write(struct Device* device, uint8_t address, const uint8_t* data, uint16_t dataSize, TickType_t timeout);
+
+bool i2c_controller_write_read(struct Device* device, uint8_t address, const uint8_t* write_data, size_t write_data_size, uint8_t* read_data, size_t read_data_size, TickType_t timeout);
+
+extern const struct DeviceType I2C_CONTROLLER_TYPE;
+
+#ifdef __cplusplus
+}
+#endif

TactilityKernel/Include/Tactility/drivers/Root.h

@@ -0,0 +1,13 @@
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct RootConfig {
+    const char* model;
+};
+
+#ifdef __cplusplus
+}
+#endif