Add procedure in documentation on how to change IP to peers

[AlessandroPaparella]

Documentation lack of clear info on how to migrate a peer on a new IP, could you add the necessary steps?
Or in alternative add a new command in horcrux binary to quickly perform this operation?

Thanks.

[agouin]

To change the DNS/IP of a cosigner:

• update config files on each cosigner
• bring all cosigners down
• remove the .horcrux/raft directory on all cosigners
• restart all cosigners

[akc2267]

#213