[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/f7/furi_hal/furi_hal_interrupt.c

@@ -1,5 +1,6 @@
 #include "furi_hal_interrupt.h"
 #include "furi_hal_delay.h"
+#include "furi_hal_os.h"
 
 #include <furi.h>
 
@@ -249,7 +250,7 @@ extern void HW_IPCC_Tx_Handler();
 extern void HW_IPCC_Rx_Handler();
 
 void SysTick_Handler(void) {
-    furi_hal_tick();
+    furi_hal_os_tick();
 }
 
 void USB_LP_IRQHandler(void) {
@@ -264,4 +265,4 @@ void IPCC_C1_TX_IRQHandler(void) {
 
 void IPCC_C1_RX_IRQHandler(void) {
     HW_IPCC_Rx_Handler();
-}
+}