Compact view mode

[sgofferj]

Is your feature request related to a problem? Please describe.

As a Nextcloud Mail user I prefer a dense UI. The message preview in the thread list is not relevant for me.

Describe the solution you'd like

I would like to see an option to turn off the preview line so that only the sender and the subject are shown. Maybe even a compact mode like in the original Horde webmail client or in Roundcube, with only sender, subject and no avatar.

Additionally, hide the separators (https://github.com/nextcloud/mail/issues/11057).

This is a opt-in user setting.

Describe alternatives you've considered

Only alternative is using another MUA

Additional context

No response