Add Bun

[privatenumber]

Would like to request for Bun to be added.

(Seems like it's already been accepted implicitly via #1849 but wanted an issue tracker)

[zloirock]

Feel free to add a PR with it.

[zloirock]

Note that it can't be just directly mapped to Safari oven-sh/bun#396

[Jarred-Sumner]

It's pretty much safe to say any non-web API which is supported in Safari Technology Preview is also supported in Bun.

From there, things like ReadableStream, URL, URLSearchParams, FormData mostly use Safari/WebKit's implementation so we can add those as well.

[zloirock]

@Jarred-Sumner compat-table does not store data for multiple Safari TP versions (and does not properly update it), so in this case, it will be impossible to store data for multiple Bun versions. Also, Bun enables some disabled Safari TP features that add some more differences.