TactilityCore improvements (#187)

FreeRTOS handles were stored plainly and they were deleted in the destructor of classes.
This meant that if a class were to be copied, the destructor would be called twice on the same handles and lead to double-free.

Seha on Discord suggested to fix this by using `std::unique_ptr` with a custom deletion function.

The changes affect:
- Thread
- Semaphore
- Mutex
- StreamBuffer
- Timer
- MessageQueue
- EventFlag

Thread  changes:
- Removal of the hack with the `Data` struct
- Thread's main body is now just a private static function inside the class.
- The C functions were relocated to static class members

PubSub changes:
- Refactored pubsub into class
- Renamed files to `PubSub` instead of `Pubsub`
- `PubSubSubscription` is now a private inner struct and `PubSub` only exposes `SubscriptionHandle`

Lockable, ScopedLockable, Mutex:
- Added `lock()` method that locks indefinitely
- Remove deprecated `acquire()` and `release()` methods
- Removed `TtWaitForever` in favour of `portMAX_DELAY`

.github/workflows/tests.yml

@@ -1,6 +1,8 @@
 name: Tests
 on:
   push:
+    branches:
+      - main
   pull_request:
     types: [opened, synchronize, reopened]
 jobs: