feat(Sticker): updates, sticker packs, and guild stickers

[advaith1]

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

• Removes deprecated sticker.asset (which is just an empty string now)
• Updates URL (old one doesn't work anymore)
• Adds sticker properties: type, packID, available, guild, guildID, user, sortValue, fetchPack(), edit(), delete(), equals()
• Adds StickerPack
• Adds Client#fetchSticker(id)
• Adds Client#fetchNitroStickerPacks()
• Renames MANAGE_EMOJIS permission to MANAGE_EMOJIS_AND_STICKERS as requested by Jethro, to reflect client update
• Adds sending stickers (stickers in MessageOptions)
• Adds Guild#stickers and GuildStickerManager
• Adds stickerCreate, stickerUpdate, and stickerDelete events
• Renames GUILD_EMOJIS intent to GUILD_EMOJIS_AND_STICKERS
• Adds sticker audit log events

discord/discord-api-docs#3127
discord/discord-api-docs#3171
discord/discord-api-docs#3128

Status and versioning classification:

• Code changes have been tested against the Discord API, or there are no code changes
• I know how to update typings and have done so, or typings don't need updating
• This PR changes the library's interface (methods or parameters added)
• This PR includes breaking changes (methods removed or renamed, parameters moved or removed)

[advaith1]

ok, I think this is ready for review?

it doesn't add GuildStickerManager or the guild sticker update gw event bc those can't really be tested now, but I've tested everything added

Stale

[kyranet]

Just three small things, otherwise LGTM

[kyranet]

Just three small things, otherwise LGTM

[SpaceEEC]

Otherwise looking good

[vladfrangu]

This needs a rebase

[iCrawl]

This needs a rebase.

[mustafa-archived]

you aware changes weren't merged?

[kyranet]

Upstream PR has landed, and this needs a rebase 😄