Add DiscordBM library to community resources

[MahdiBM]

Hello everyone.
By this PR, I'm trying to propose DiscordBM as a "community library" to be added to the community resources in Discord docs.
Please let me know if there is a better place to do this.
Also I don't mind if this PR gets rejected. I just thought it's worth proposing since I see no Swift libraries in the list.

Why

• DiscordBM is in Swift's Official SSWG (Server-Side Working Group)'s incubation program since 2023, which tries to ensure longevity of the projects. See the related web page on swift.org: https://www.swift.org/sswg/incubated-packages.html.
• In public development since August 2022. 127 stars currently, 866 commits on the main branch (1000+ if you consider the squashed commits).
• Supports pretty much all bot APIs, except Voice.
• Properly handles HTTP rate limits and Gateway rate limits.
  • There are configurable auto-retry mechanisms. For example by default if Discord mentions that a request needs to be retried in 5 seconds or less, the library just retries the request instead of shooting the error at user's face.
  • Other kinds of ratelimits (like global ratelimits, or interaction ratelimits) are also respected and there are tests for these as well.
• Contains a lot of Integration tests that actually call Discord to ensure the library works in practice as well.
  • Including Gateway connection integration tests.
  • Including REST API endpoint tests for all endpoints where it was possible.
    • For example some interaction endpoints can't be easily triggered via an automation, with acceptable parameters.
• The library goes "above and beyond" in some instances as well, and is not just a minimal implementation.
  • For example using Gateway compression is enabled, and I recently updated the library to use the more-performant zstd compression algorithm.
  • Or it contains a dedicated UnstableEnum macro, which might sound "ok" to you, but only someone who uses Swift on the daily would appreciate.
    • The enum ensures full usability and compatibility even if Discord introduces a new "case" to some of the APIs "enum"s.
  • Some other such instances, off-hand, are DiscordCache, REST API cache, payload validation, permission checker, and DiscordUtils.
• Consistently maintained over the years. Yes, I haven't been the fastest to support the new features recently, but the library has been consistently updated at least every few months ever-since its inception.

If someone from the Discord team wants to see how much DiscordBM is used, this is the User-Agent header that the library uses: DiscordBM (https://github.com/discordbm/discordbm, 1.0.0), and the library also sends DiscordBM as the browser in Gateway connections. I'm also curious to know.

I do think DiscordBM is not super popular at the scale of likely all the other featured libraries, but we're doing what we can do considering Swift's server-side community is still "up and coming", and I think it's important for Swift to have a showing in the list.
If needed, I can ask some folks from the SSWG to vouch for the library so you can feel more comfortable making this change.

[Soheab]

See #7873 (comment)

[MahdiBM]

Thanks for the link @Soheab.

I understand that there is a "revamp" coming in sometime, and I also do realize that DiscordBM likely doesn't have "1000 active bots" (It's not practical to expect a Swift Discord library to have 1000 active bots, so essentially that just excludes the Swift language as a whole).

I'm still hoping for the possibility to hear something like this:
#7157 (comment)
In the sense of "It is quite feature-complete and is practically the only discord library out there for C Swift.".

(DiscordBM is practically the only Swift library. The other libraries you can find are either not well-maintained, or miss important features, or are mostly a copy of DiscordBM anyway, or all three. We can talk about the other libraries if you want.)

If that's not possible, someone from the Discord team can close the PR.