msteamsbridge: going out of maintenance

[DeepDiver1975]

owncloud/msteamsbridge is being archived and will no longer be maintained.
Please update the documentation to remove or deprecate its pages and references.

• Archived repo: https://github.com/owncloud/msteamsbridge
• README archive notice: https://github.com/owncloud/msteamsbridge/pull/45

[DeepDiver1975]

The Microsoft Teams (msteamsbridge) documentation lives in the owncloud/docs-server content repo, not in this aggregator repo (owncloud/docs only assembles the Antora sources). No references exist here.

Opened a cleanup PR against docs-server: owncloud/docs-server#1561

It removes the two MS-Teams integration pages (end-user + admin), the now-empty classic_ui Integration section, the admin nav/index Teams entries (Splunk integration retained), the App: Microsoft Teams Bridge config sample, and rewords the .htaccess upgrade note that linked the removed page. Verified 0 remaining msteamsbridge|ms-teams|microsoft teams references and no dangling xrefs.