Thread, Timer and flash.sh improvements (#165)

- Various improvements to Thread and Timer:
  - Remove "mark as static" option as it is unused
  - Implemented core pinning for ESP32 platforms
  - Use `TickType_t` consistently (instead of `uint32_t`)
  - Use `enum class` instead of `enum`
- Fix for `flash.sh` not working when using `pip` to install `esptool`

Boards/Simulator/Source/Main.cpp

@@ -29,7 +29,7 @@ void freertosMain() {
         "main",
         8192,
         nullptr,
-        tt::Thread::PriorityNormal,
+        static_cast<UBaseType_t>(tt::Thread::Priority::Normal),
         nullptr
     );