Moved and renamed files for consistent C code style (#463)

* **Documentation**
  * Added new C coding style guide detailing naming conventions for files, directories, macros, constants, variables, functions, and type definitions with illustrative examples.
  * Updated C++ coding style documentation with clarifications on C naming conventions and header directory organization patterns.

* **Refactor**
  * Updated header include paths throughout the codebase to use lowercase naming conventions consistently.

CODING_STYLE_C.md

@@ -0,0 +1,96 @@
+# C coding Style
+
+## Naming
+
+### Files
+
+Files are lower snake case.
+
+- Files: `^[0-9a-z_]+$`
+- Directories: `^[0-9a-z_]+$`
+ 
+Example:
+```c
+some_feature.c
+some_feature.h
+```
+
+### Folders
+
+Project folders include:
+- `source` for source files and public header files
+- `private` for private header files
+- `include` for projects that require separate header files
+
+### Macros and consts
+
+These are all upper snake case:
+
+```c
+#define MY_CONST 1
+#define PRINT_SOMETHING() printf("something")
+const int ANOTHER_CONST = 1;
+```
+
+### Variables
+
+Variable names and function parameters are lower snake case:
+
+```c
+int some_variable;
+```
+
+### Enumerations and Structs
+
+Enums and struct types are upper camel case.
+Its fields use lower snake case.
+
+```c
+struct ThreadData {
+    int some_attribute;
+};
+```
+
+```c
+enum SomeResult  {
+    Ok,
+    NotSupported,
+    Error
+};
+```
+
+### Function names
+
+Function names are lower snake case.
+
+Example:
+
+```c
+void get_limit() {
+    // ...
+}
+```
+
+If a set of functions relates to a `struct`, the CamelCase struct name is converted to a snake_case_ prefix for the function name:
+
+```c
+struct TextMessage {
+    // ...
+};
+
+void text_message_set(struct TextMessage* message) { /* ... */ }
+
+void text_message_get(struct TextMessage* message) { /* ... */ }
+
+```
+
+### Typedef of simple value types
+
+Typedefs for simple value types (such as int, int64_t, char) are lower snake case.
+They are postfixed with `_t`
+
+Examples:
+
+```c
+typedef uint32_t thread_id_t;
+```