Render markdown image syntax in documentation. Relative URLs are fetched from the project directory; absolute URLs are hotlinked from wherever they point.
Syntax and URL resolution:
```
# In New_Project27/src/Main.enso
## Main method docs
- Image at `New_Project27/src/image.jpg`: 
- Image at `New_Project27/image.png`: 
- Image at `New_Project27/src/image.jpg`: 
- Image at `New_Project27/image.png`: 
main =
42
```
https://github.com/enso-org/enso/assets/1047859/3f873f3f-31b1-44bf-ae3e-2f467f2d546dCloses#10058.
# Important Notes
Stacked on #10064.
Fixes#8520
If the websocket is closed not by us, we automatically try to reconnect with it, and initialize the protocol again. **Restoring state (execution contexts, attached visualizations) is not part of this PR**.
It's a part of making IDE work after hibernation (or LS crash).
# Important Notes
It required somewhat heavy refactoring:
1. I decided to use an existing implementation of reconnecting websocket. Replaced (later discovered by me) our implementation.
2. The LanguageServer class now handles both reconnecting and re-initializing - that make usage of it simpler (no more `Promise<LanguageServer>` - each method will just wait for (re)connection and initialization.
3. The stuff in `net` src's module was partially moved to shared's counterpart (with tests). Merged `exponentialBackoff` implementations, which also brought me to
4. Rewriting LS client, so it returns Result instead of throwing, what is closer our desired state, and allows us using exponentialBackoff method without any wrappers.
This is a set of split off changes made as a side effect while working on engine reconnection handling.
Cleaned up GUI e2e setup, unified as much of the entrypoint code as possible. Currently the only real difference between the real and testing entrypoint is mocking of all network calls and not loading through dashboard.
I've managed to completely get rid of `MockApp`, and remove tricky mocking of pinia stores.
