This commit refactors the OS startup functions as follows:
- Moved the OS/app startup functions listed below to "app_startup.c". Their
implementations are now common to all ports (RISC-V and Xtensa) of all
FreeRTOS implementations (IDF and Amazon SMP).
- esp_startup_start_app()
- esp_startup_start_app_other_cores()
- Removed esp_startup_start_app_common() as app startup functions are now
already common to all ports.
- Added extra logs to "main_task" to help with user debugging
Note: Increased startup delay on "unity_task". The "unity_run_menu()" is non
blocking, thus if the main task or other startup tasks have not been freed
by the time "unity_run_menu()" is run, those tasks will be freed the next time
"unity_task" blocks. This could cause some tests to have a memory leak, thus
the "unity_task" startup delay has increased.
