Improve flow of going on vacation / being unavailable

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

When you go on vacation or are unavailable for an extended period of time, you currently need to do several things manually:

• Set a mail auto responder
• Add the info to a vacation calendar of the organization
• Possibly add an event to your own calendar as well so you are set as busy
• Set a status message and do not disturb
• Let your teams in Talk know that you are on vacation (if you have a main team channel for example, a notice could be posted there at the start)
• Also when people mention you in Talk, they could have an auto reply (possibly only visible to them) noting your status (yes we do have it in the @-mention dropdown, would just be a nice addition for visibility)
• Maybe even vacation request handling via Tables – when it's approved, the preset is ready

Describe the solution you'd like

It would be very nice if this could be more integrated and automated.

The relevant info you need to set would be:

• From when are you unavailable?
• When are you back?
• Who is your replacement? (optional, cause this is not relevant in e.g. school case)

So very simple, just a range picker and a "person" picker. Those could then be used to automatically fill the status and the vacation replies.

It could also show the number of remaining vacation days so you are pushed to use them before they expire. This would go toward the "digital wellbeing" goal.

Work packages

• https://github.com/nextcloud/server/issues/40397
• https://github.com/nextcloud/server/issues/40398
• https://github.com/nextcloud/server/issues/31177

This could be a possible integration feature among Talk, Calendar, status which has a focus on collaboration – or rather to cover the case where collaboration is not possible. cc @karlitschek @AndyScherzinger @nickvergessen @ChristophWurst @PVince81