docs: refactor tabs

[moskalakamil]

Documentation structure

• Introduced a new Fundaments section (Intro, Installation, Configuration).
• Reorganized existing docs by moving and renaming pages (e.g. With Expo / Without Expo).
• Cleaned up navigation, links, and sidebar ordering.
• Split and clarified Player docs (useVideoPlayer, VideoPlayer, lifecycle, events).

Analytics

• Added a new Player → Analytics section (marked as NEW):

  • Simple (JS Events) – lightweight analytics via useEvent
  • Manual (Native) – full native integration examples for Android (ExoPlayer) and iOS (AVPlayer), including available metrics and architecture

Offline Video SDK (PRO)

• Added comprehensive Player → Downloading documentation (marked as PRO):

  • Getting Started & installation
  • Full API reference
  • Download events
  • Track selection
  • DRM downloading (persistent licenses, FairPlay/Widevine notes)

VideoView & Plugins

• Introduced a dedicated VideoView section (props, events, methods, chapters).
• Added a Plugins section with guides, registry docs, and “Ask for Plugin”.

UI & tooling

• Enabled sidebar customProps (badges like NEW, PRO) via @widlarzgroup/docusaurus-ui.
• Updated Docusaurus config and sidebars to support typed sidebars.
• Minor config and dependency updates.