configure does not survive PKI keys

[jhps]

In 2.5 (65305af), a configuration that has privateKey, publicKey, or adminKeys causes the cli to exit with:
Aborting due to: expected bytes, str found

It seems that MessageToDict() converts bytes to base64 strings that are saved in the config yaml but when these are are later loaded into a config to be sent a setattr() of a string to a bytes field causes an exception.

[contra-bit]

I'd like to mention that also the Python CLI has an issue with serializing public keys, which always converts them to a string or bytes, regardless of the input format. This should be fixed to ensure consistent behavior.

Fixes:

• Fix the Python CLI issue with serializing public keys.

All of these examples produce the same error.

meshtastic --set security.is_managed true --set security.admin_key b'XXXXXXXXXXXXXXXXXXXXXXXXXX' --set security.admin_channel_enabled true
meshtastic --set security.is_managed true --set security.admin_key XXXXXXXXXXXXXXXXXXXXXXXXXX --set security.admin_channel_enabled true
meshtastic --set security.is_managed true --set security.admin_key 'XXXXXXXXXXXXXXXXXXXXXXXXXX' --set security.admin_channel_enabled true

In the example with: b'XXXXXXXXXXXXXXXXXXXXXXXXXX' it tries to add the b to the bytes

The fix should also document how to add multiple admin keys as per meshtastic/web#315