DH keys too small after conversion --> Dovecot does not allow logins --> Suggest auto-fix after conversion

[Bitpalast]

Is your feature request related to a problem? Please describe.
After the conversion of a server, Dovecot email login was no longer possible due to short keys used on the server.

Describe the solution you'd like
https://support.plesk.com/hc/en-us/articles/12377016572439-Unable-to-log-in-to-Roundcube-webmail-or-using-email-client-on-Plesk-server-Can-t-load-DH-parameters-dh-key-too-small

# plesk sbin sslmng --service dovecot --strong-dh --dhparams-size=2048
(fixed it)

Describe alternatives you've considered
n/a

Additional context
Maybe it would be good if the script could check whether the issue described in the KB article exists after a conversion and then automatically run the dhparams-size command to increase the key size.

[SandakovMM]

The problem should be fixed in #191.