update to Nextcloud 29

[szaimen]

Tasks

TODO:

• Wait for at least 29.0.1
• Wait for publish new images after recent PRs are merged and tested #4653 to become stable

Issues:

• https://github.com/nextcloud/server/issues?q=is%3Aopen+is%3Aissue++label%3A29-feedback+
• Revert: "Check datadirectory owner, not config owner." server#45302
• change the rewrite for remote.php #4651

Apps not compatible:

• increase aio version to 29
• other bundled apps
• further apps

Test:

• test new instance?
• check if all included features work
  • ClamAV
  • Collabora
  • Fulltextsearch
  • Imaginary (for previews of heic, heif, illustrator, pdf, svg, tiff and webp. Imaginary is currently incompatible with server-side-encryption)
  • talk recording
• check admin overview
• check each other overview
• check if nextcloud-aio app works
• remove potentially added note in the aio interface about nextcloud 28 by changing newMajorVersion to ''
• update postgres to 16 with Nextcloud 29 #3573
• ...