Add option to preserve private key for factory reset (config) (#4679)

* Add option to preserve private key for factory reset (config)

* Typo fix

* Copy the key in the right direction, and set the size.

* Don't set the key size back to 0 right after setting it to 32.

* Set the key size before using it to do a memcpy.

* Use the right key_size for backing up private_key

* Don't factoryReset() for a missing nodeDB

* Disable Bluetooth in AdminModule when resetting device settings or nodeDB to avoid race

* Add checks for valid objects before deinit bluetooth

* Add disableBluetooth to handleSetConfig, handleSetModuleConfig, and commit settings

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Co-authored-by: Jonathan Bennett <jbennett@incomsystems.biz>

src/mesh/NodeDB.h

@@ -182,7 +182,8 @@ class NodeDB
     void cleanupMeshDB();
 
     /// Reinit device state from scratch (not loading from disk)
-    void installDefaultDeviceState(), installDefaultChannels(), installDefaultConfig(), installDefaultModuleConfig();
+    void installDefaultDeviceState(), installDefaultChannels(), installDefaultConfig(bool preserveKey),
+        installDefaultModuleConfig();
 
     /// write to flash
     /// @return true if the save was successful