Add new --password option and wire it to go to amari.connect(password=...)

Support for password-based authentication in amari.connect was just
added in the previous patch.

We need to extend filtering of logged fields on service attach a bit
since now the first service message can be both 'ready' and
'authenticate', and besides e.g. 'message' we don't want to log what was
the 'challenge'.

/reported-and-tested-by @lu.xu
/reviewed-on !6