feat: interactions

[vaporoxx]

Please describe the changes this PR makes and why it should be merged:

Attempt #​2! Most of the logic is taken from #5106, but with a giant refactor, most notably the interaction client class being removed and an application command manager class being added. To see a quick example of how this branch is structured, have a look here.

Additionally, this PR also adds the new USE_APPLICATION_COMMANDS permission, the APPLICATION_COMMAND message type and the EPHEMERAL and LOADING message flags.

Status and versioning classification:

• I know how to update typings and have done so
• This PR changes the library's interface (methods or parameters added)

[izexi]

Just some minor nits

[trulyronak]

Curious — what still needs to be done to get slash commands in, and how can outside developers in the community help? Really looking forward to being able to use discord.js for slash commands, and would be interested in helping out

[monbrey]

Curious — what still needs to be done to get slash commands in, and how can outside developers in the community help? Really looking forward to being able to use discord.js for slash commands, and would be interested in helping out

There's nothing specific that needs to be done that wouldn't already be in the comments here. The PR is pending reviews and approvals from the maintainers.

We've also had to keep up with ongoing changes from Discord - the API has only reached a state of stability quite recently.

[neolectron]

🎉

[gruselhaus]

Wohoooo 🎉

[Dcai169]

Any eta on when this will be part of a release?

[kyranet]

Any eta on when this will be part of a release?

Soon:tm:, we'll go thru all the semver: major PRs and review/merge those, then we'll release v13.

[Flo4604]

If someone wanted to use it as I do npm i discordjs/discord.js#master works just fine

[VimperSky]

If someone wanted to use it as I do npm i discordjs/discord.js#master works just fine

you can just use npm i discordjs/discord.js because master is default branch