NRF52 - power management improvements (#9211)

* minor NRF52 test cleanup

* detect USB power input on ProMicro boards

* prevent booting on power failure detection

* introduce PowerHAL layer

* powerHAL basic implementation for NRF52

* prevent data saves on low power

* remove comment

* Update src/platform/nrf52/main-nrf52.cpp

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Update src/power/PowerHAL.h

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Update src/main.cpp

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Merge missing voltage threshold comparison

* add missing variable

* add missing function declaration

* remove debug strings

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Ben Meadors <benmmeadors@gmail.com>

src/power/PowerHAL.cpp

@@ -0,0 +1,19 @@
+
+#include "PowerHAL.h"
+
+void powerHAL_init()
+{
+    return powerHAL_platformInit();
+}
+
+__attribute__((weak, noinline)) void powerHAL_platformInit() {}
+
+__attribute__((weak, noinline)) bool powerHAL_isPowerLevelSafe()
+{
+    return true;
+}
+
+__attribute__((weak, noinline)) bool powerHAL_isVBUSConnected()
+{
+    return false;
+}