bugfix/rtc_clk_32k_bootstrap: Fix starting 32k RTC

1. External 32kHz crystal is started for too long or it may not start at all. It is often observed at the first start.
2. At the first start, it is possible that the crystal did not start. And the recorded period was recorded as 0. Which led to a division error by zero during the transition to the deep sleep mode (Maybe somewhere else).
3. Added a unit test to test a new method of oscillation an external crystal.
4. Added a new method of oscillating of an external crystal. The legs of the crystal are fed with a 32 kHz frequency.

The new method eliminates these errors.

Added unit test: `\esp-idf\components\soc\esp32\test\test_rtc_clk.c`: `make TEST_COMPONENTS=soc`
- 8 Test starting external RTC crystal. Will pass.

`Bootstrap cycles for external 32kHz crystal` - is specified in the file Kconfig by default 100.

QA tested a new method of oscillation the crystal on 25 boards. The supply of square waves on the crystal showed a 100% result in contrast to the previous method of launching the crystal. After the tests, the old method was deleted.

Closes TW19143

components/esp32/esp_clk_internal.h

@@ -37,3 +37,8 @@ void esp_clk_init(void);
  * This function disables clock of useless peripherals when cpu starts.
  */
 void esp_perip_clk_init(void);
+
+/* Selects an external clock source (32 kHz) for RTC.
+ * Only internal use in unit test.
+ */
+void rtc_clk_select_rtc_slow_clk();