Perf: Optimize pages loading (Filecache path like approach)

[Koc]

📝 Summary

This is alternative approach to #2390 that fixes same performance issue (closes #2380).

Benefits comparing to previous implementation:

• no extra columns
• no migration to re-process already existent page
• no listeners
• much simpler implementation

So, we're just load all necessary pages via simple query SELECT * FROM filecache WHERE storage_id = <storageId> AND path LIKE 'appdata_<instanceId>/collectives/<collectiveId>/%'

🖼️ Screenshots

Collective with 390 pages with various nesting level

🏚️ Before	🏡 After
747 queries - depends on pages count and nesting level	50 queries - more or less constant

🚧 TODO

• As a future improvement we can consider to add index to filecache table to storage_id, path columns (but this requires extra PR to nextcloud/server)

🏁 Checklist

• Code is properly formatted (npm run lint / npm run stylelint / composer run cs:check)
• Sign-off message is added to all commits
• Tests (unit, integration and/or end-to-end) passing and the changes are covered with tests
• Documentation (README or documentation) has been updated or is not required

🤖 AI (if applicable)

• The content of this PR was partly or fully generated using AI tools
• The AI-generated content was reviewed, comprehended and tested by a human