fix(files): combine navigation and files list into single Vue app

[ShGKme]

• Resolves: Leave only onemain landmark on files page #43085
• See discussion enh(NcContent): Add skip content buttons nextcloud-libraries/nextcloud-vue#4983 (comment)
  

Summary

During files2vue migration, files were migrated as two Vue apps:

• Navigation = <NcAppNavitation>
• FilesList = <NcAppContent>

But Vue app in Nextcloud is supposed to be one NcContent app that contains navigation and content.

After migration has finished there is no need to separate Navigation and FilesList.

TODO

• Combine Navigation and FilesList into one Files App
• Remove any custom content from PHP template for files
  • There were two hidden inputs, but they are not used anymore
• Check that public share is still working

Screenshots

No visual changes on both user files and public share

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[JuliaKirschenheuter]

works great, thank you!

[JuliaKirschenheuter]

/backport b40279e to stable28