irc: handle ERR_NICKLOCKED (902)
irc: add option irc.server.*.sasl_disconnect_on_fail (task #12204)
Merge branch 'feature/sasl_disconnect_on_fail' of git://github.com/maxteufel/weechat into maxteufel-feature/sasl_disconnect_on_fail
irc: merge arrays with server options names and default values into a single array
irc: rename server option "sasl_disconnect_on_fail" to "sasl_fail", change type to integer (enum)

New possible values are:
- "continue": ignore the SASL failed (continue connection to server
  without authentication)
- "reconnect": disconnect and schedule a reconnection to server
- "disconnect": disconnect
core: update translations
core: update ChangeLog (closes #265, task #12204)