[Vue Rewrite] Fix css issues and start updating docs

[devlinjunker]

Related to #748

💡 Tips for Reviewer:

• Switch to markdown preview mode for reviewing docs changes
• ideally someone can test this who doesn't have the cron warning on their machine.. I'm pretty sure this will fix the issue mentioned in [Vue Rewrite] Basic Mobile accessible interface #2371

🗒️ Summary

• Fixes issue described in [Vue Rewrite] Basic Mobile accessible interface #2371 and discussed here
  • use #content for Vue selector
  • use Vue Application app.error popover to display cron warning
  • Add links array to error object that can display help links in the error/warning message
• Fixes Explore Page CSS
• Start updating the Doc pages (Frontend Plugin section is TODO until we rewrite that...)

✅ Checklist

• Code is properly formatted
• Sign-off message is added to all commits

- [ ] Changelog entry added for all important changes.

📷 Visual

Cron Warning:

Using Placeholder Color for viewed Items:

Explore Page:

➡️ Up Next

• Settings in Sidebar (@scottdotau I think I'll start on this soon unless you're making progress - I'll try to start by looking into the backend requests + application behavior before the component..)
  • Component
  • Backend Requests + Application Behavior Changes
    • Keyboard Navigation
    • Mark on Scroll
    • Reverse Order (Oldest to Newest)
    • Upload/Download Subscriptions/Articles

@Grotax I think both of these can be done after a beta release:

• use ?selected=<id> url query parameter to store and parse which Feed Item is displayed in FeedItemDisplay (this will be useful for implementing the search bar - and allow navigating directly to the specific feed item)
  • Also need to update search provider php code
  • Update Documentation?
• addArticleAction Plugin API
  • Nextcloud News Code
  • Add to Bookmarks Example Plugin
  • Add New Frontend/JS Plugin Documentation

[Grotax]

Hey, looks good :)

The gap is gone and the UI works for me.

Regarding your other points I agree with that :)