Add recoverwallet RPC call

[lontivero]

This PR adds a new method to recover wallets from mnemonics. Close: #11362

Using curl

$ curl -s \
  --user <rpcuser:rpcpassword> \
  --data-binary '{"jsonrpc":"2.0", "id":"curltext", "method":"recoverwallet", "params":["recovered-wallet", "emerge title hero sauce pilot mail breeze jelly fatal speak shock ladder"]}' \
  -H \
  -- 'content-type: text/plain;' \
  http://127.0.0.1:37128/

Using wcli

$ ./wcli.sh \
  recoverwallet recovered-wallet \
  "emerge\ title\ hero\ sauce\ pilot\ mail\ breeze\ jelly\ fatal\ speak\ shock\ ladder\"

[MarnixCroes]

tack ece3b93
(tried both curl and wcli, and with a password)

Would be nice to return a message if it was successfull -> wallet succesfully recoverd.

[lontivero]

Would be nice to return a message if it was successfull

RPC is for computers, they can see the http error code 200 OK in the header.