Pwnagotchi's identity protection

[V0r-T3x]

Is your feature request related to a problem? Please describe.
When a crash happen, the RSA keys can be corrupted and the keys need to be generated again. The pwnagotchi identity is lost.

Describe the solution you'd like
The keys and fingerprint should be save into a backup and loaded if the pwnagotchi detect a corruption of those files.

Describe alternatives you've considered
I didn't see an alternative for this problem and I actually coded the modification for it. It's tested since a while and already integrated into fancygotchi as a protection for the pwnagotchi identity in case of crash of the view.py file.

Additional context
N/A