Previously, only the main identity of an account would get the proper SMTP
server assigned. Identities corresponding to aliases would not get an SMTP
server assigned at all, leading to a (Thunderbird-internal) fallback to the
SMTP server associated to the primary account. This is obviously wrong for
non-primary accounts having aliases associated to them. Fix it by specifying
the SMTP server explicitly for all identities.
The identity's signature will be configured according to signature.text
and signature.showSignature. Signature commands are not supported by
Thunderbird.
The added extraConfig option allowes users to insert custom text at
the end of the generated profile `user.js` file. This allows the users
to import templates as part of their configuration.
Add a new Thunderbird module that uses the configuration in
`accounts.email.accounts` to setup SMTP and IMAP accounts.
Multiple profiles are not supported at this point.
