[FL-2480] Use SysTick as the main OS timer (#1140)

* Use SysTick as OS tick timer
* Use LPTIM2 as tickless idle timer
* Remove dummy LPTIM2 IRQ handler
* Clean up clock init code
* Rename os timer to idle timer
* Advance hal ticks along with FreeRTOS's
* Improve SysTick control during tickless idle
* Improve idle timer precision
* Correct SysTick IRQ priority
* Main, FuriHal: move system startup to separate thread
* Minor code cleanup

Co-authored-by: Aleksandr Kutuzov <alleteam@gmail.com>

firmware/targets/furi_hal_include/furi_hal_delay.h

@@ -18,11 +18,6 @@ void furi_hal_delay_init();
 /** Get instructions per microsecond count */
 uint32_t furi_hal_delay_instructions_per_microsecond();
 
-/** Increase tick counter.
- *  Should be called from SysTick ISR
- */
-void furi_hal_tick(void);
-
 /** Get current tick counter
  *
  * System uptime, may overflow.