refactor(language-server): architecture improvements

[johnsoncodehk]

Public Changes

• Server context is now passed to the ServerProjectProvider via this arg, so the ServerProjectProviderFactory interface is no longer needed.
  • Rename createTypeScriptProjectProviderFactory to createTypeScriptProjectProvider
  • Rename createSimpleProjectProviderFactory to createSimpleProjectProvider
• initialize method parameters are simplified, getLanguagePlugins and watchFileExtensions are no longer needed.
• The watchFiles method has been added to replace the old watchFileExtensions option, which will allow file extensions that require watch to be calculated after language plugins are loaded.

For more detailed changes, please refer to the actual type changes.