feat: implement downloader

[nhedger]

This PR implements a downloader that prompts users to download the Biome CLI if none is found. It is meant to replace the current strategy of bundling the CLI with the extension with every release.

Screen.Recording.2023-11-03.at.19.00.54.mov

Testing

1. pnpm install
2. F5
3. Create a new folder with a biome.json file inside
4. Open that folder
5. Click on the biome.json file
6. A notification stating that biome is not installed should appear. click download
7. When biome is installed, try formatting a file
8. Click on the biome status bar, downgrade the version, the version should change

Fair warning

The code is admittedly a bit spaghetti, but I think it will do fine for now. We'll have to overhaul the majority of the logic if we want to support testing and more features in the future.

[SuperchupuDev]

does the node version used in the minimum supported vscode version support global fetch? if so we could use it and avoid adding an additional dependency, or use undici's fetch which node uses under the hood, or i might be wrong altogether as i havent ever worked on vscode extensions

[nhedger]

I believe Node's fetch API was released with Node 18. The version of Node used by the minimum supported version is Node 16.

That being said, in reading your comment I realize that I haven't confirmed that it works with 1.80 either, so I'll do that.

[nhedger]

As expected, it did not work. I was able to polyfill fetch with ofetch, so we'll keep the dependency anyway for now.

[Conaclos]

Great work!

[ematipico]

Overall it looks good to me, and I think it's an excellent feature! I left some suggestions

[nhedger]

I ended up adding the command for clearing the versions cache if only to be used by us while developing the extension.