Improve handling of links for online events

[ChristophWurst]

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

As a user of online meetings I want a smooth experience for links I have to open to join a call.

Describe the solution you'd like

1. Write the conference URL into the location field when creating Talk rooms for an event. feat: Write Talk URL into location, not description #5395
2. Implement a clickable link for the location field. make links clickable in locations and description areas - rel: #5030 #5355
3. Render the location field as a clickable link in the appointment notification mail (if it contains a link). feat(caldav): linkify location in scheduling mails server#39753

Describe alternatives you've considered

No response

Additional context

This is an alternative approach to #1758 while it's poorly supported by other clients.

[tcitworld]

I don't think 3. can be made with the current email template system. Maybe with the help of nextcloud/server#38093 ? 😼

[ChristophWurst]

\OCA\DAV\CalDAV\Schedule\IMipService::addMoreOptionsButton renders the "More options…" in emails. Can we use that?

[st3iny]

Clickable links in mails still need to be done.