Convert !commands to slash commands

[nickserv]

Inspired by #46

Application commands provide a better UX for running bot commands in Discord (fixing common issues of ours like moderators having to delete commands that users accidentally run) while also allowing for more relaxed bot permissions.

Once we upgrade to discord.js 13, we can use their registering slash commands example.

[vcarl]

This seems like one benefit we'd get by updating discord.js, maybe that's a better title?

[nickserv]

I'm intentionally keeping this as a separate issue, since this is more of a UX improvement and the handler format is not required in discord.js 13. Neither PR has this yet, and I might move the refactor to another PR anyway to make it easier to review.

[nickserv]

Renaming to specifically use slash commands, since we don't seem to need the other application command types (user and message context menu commands) yet. Slash commands are specifically used when typing messages, which is most similar to how we're currently using the bot.

[Padmanabh82]

Ye, we need this

[nickserv]

What's the status of this? I noticed another PR got merged, but I'm not seeing our slash commands on Discord.

[vcarl]

I haven't made any changes to affect this, but I did implement command deployment in #198 which should facilitate this. Our only command atm is the anonymous report

reactibot/scripts/deploy-commands.ts

Line 27 in 7f3bbcd

const cmds: CommandConfig[] = [report];