common: Limit UART console baud rate if power management is enabled

Also add some comments explaining how the console settings are used by both
bootloader and app.

Based on config bug and discussion here: https://esp32.com/viewtopic.php?f=2&t=16111&p=61520#p61520

components/esp_common/Kconfig

@@ -99,8 +99,13 @@ menu "Common ESP-related"
         depends on ESP_CONSOLE_UART_CUSTOM
         default ESP_CONSOLE_UART_CUSTOM_NUM_0
         help
-            Select which UART peripheral to use for console output.
-            On ESP32, UART2 is not supported for console output via ets_printf.
+            This UART peripheral is used for console output from the ESP-IDF Bootloader and the app.
+
+            If the configuration is different in the Bootloader binary compared to the app binary, UART
+            is reconfigured after the bootloader exits and the app starts.
+
+            Due to an ESP32 ROM bug, UART2 is not supported for console output
+            via ets_printf.
 
         config ESP_CONSOLE_UART_CUSTOM_NUM_0
             bool "UART0"
@@ -121,6 +126,12 @@ menu "Common ESP-related"
         range 0 46
         default 1 if IDF_TARGET_ESP32
         default 43 if IDF_TARGET_ESP32S2
+        help
+             This GPIO is used for console UART TX output in the ESP-IDF Bootloader and the app (including
+             boot log output and default standard output and standard error of the app).
+
+             If the configuration is different in the Bootloader binary compared to the app binary, UART
+             is reconfigured after the bootloader exits and the app starts.
 
     config ESP_CONSOLE_UART_RX_GPIO
         int "UART RX on GPIO#"
@@ -128,13 +139,35 @@ menu "Common ESP-related"
         range 0 46
         default 3 if IDF_TARGET_ESP32
         default 44 if IDF_TARGET_ESP32S2
+        help
+            This GPIO is used for UART RX input in the ESP-IDF Bootloader and the app (including
+            default default standard input of the app).
+
+            Note: The default ESP-IDF Bootloader configures this pin but doesn't read anything from the UART.
+
+            If the configuration is different in the Bootloader binary compared to the app binary, UART
+            is reconfigured after the bootloader exits and the app starts.
+
 
     config ESP_CONSOLE_UART_BAUDRATE
         int
         prompt "UART console baud rate" if ESP_CONSOLE_UART_CUSTOM
         depends on ESP_CONSOLE_UART
         default 115200
-        range 1200 4000000
+        range 1200 4000000 if !PM_ENABLE
+        range 1200 1000000 if PM_ENABLE
+        help
+            This baud rate is used by both the ESP-IDF Bootloader and the app (including
+            boot log output and default standard input/output/error of the app).
+
+            The app's maximum baud rate depends on the UART clock source. If Power Management is disabled,
+            the UART clock source is the APB clock and all baud rates in the available range will be sufficiently
+            accurate. If Power Management is enabled, REF_TICK clock source is used so the baud rate is divided
+            from 1MHz. Baud rates above 1Mbps are not possible and values between 500Kbps and 1Mbps may not be
+            accurate.
+
+            If the configuration is different in the Bootloader binary compared to the app binary, UART
+            is reconfigured after the bootloader exits and the app starts.
 
     config ESP_CONSOLE_USB_CDC_RX_BUF_SIZE
         int "Size of USB CDC RX buffer"
@@ -264,4 +297,4 @@ menu "Common ESP-related"
     config ESP_MAC_ADDR_UNIVERSE_ETH
         bool
 
-endmenu # Common ESP-related
+endmenu # Common ESP-related