Implement new Enso documentation parser; remove old Scala Enso parser.
Performance: Total time parsing documentation is now ~2ms.
# Important Notes
- Doc parsing is now done only in the frontend.
- Some engine tests had never been switched to the new parser. We should investigate tests that don't pass after the switch: #5894.
- The option to run the old searcher has been removed, as it is obsolete and was already broken before this (see #5909).
- Some interfaces used only by the old searcher have been removed.
This PR implements HTML generation from documentation IR for all suggestion database entries and replaces the old documentation panel with a newer one.
Additional adjustments to the looks of the documentation would be applied separately in a future PR. This PR focuses on the fastest possible delivery of a usable documentation panel. We want to test it in real-world use cases and gather feedback for future improvements.
Documentation demo scene with mocked data:
https://user-images.githubusercontent.com/6566674/213436313-88753ed8-346f-423e-956e-7db39f5dc266.mp4
Component browser with actual engine-provided data:
https://user-images.githubusercontent.com/6566674/213436375-d0ec074b-f7a6-4deb-a7de-3adee999cc86.mp4
# Important Notes
- Fixed language protocol data structures.
- Scrolling to the selected method is also implemented here.
- Also, the selected item is highlighted with yellow.
- Only some pieces of information we have are displayed. For example, we don't display return types for methods or types of arguments.
- A bunch of code related to previous implementation is removed, but probably not all of it.
