Managesieve: Add ability to remove 'redirect' option from UI

[tomsommer]

Mailservers can opt to not allow the Sieve redirect functionality to work, (Dovecot has sieve_max_redirects=0).

There is no way to hide the redirect option from the Roundcube Managesieve UI, so the option is always displayed even if the functionality is disabled.

It would be nice with a hook or plugin config option to hide/disable 'redirect' from appearing in the Roundcube UI.

[alecpl]

Implemented. Configuration as follows: $config['managesieve_disabled_actions'] = ['redirect'];

[the-djmaze]

@tomsommer did you also request this at MS Outlook, Thunderbird, Kmail, Imail, etc. etc.
Because there the option is still active due to RFC 5228 section 4.

https://datatracker.ietf.org/doc/html/rfc5228#section-4

Implementations MUST support the "keep", "discard", and "redirect" actions.

https://datatracker.ietf.org/doc/html/rfc5228#section-4.2

Implementations MAY ignore a redirect action silently due to policy
reasons. For example, an implementation MAY choose not to redirect
to an address that is known to be undeliverable. Any ignored
redirect MUST NOT cancel the implicit keep.