Bring server config juggling into MatrixChat
Bring server config juggling into MatrixChat

This way the server config is consistent across login, password reset, and registration. This also brings the code into a more generic place for all 3 duplicated efforts.
matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk