[chore] Remove unused m2m tables status_to_emojis and account_to_emojis

[tsmethurst]

Since #1073 and #1074 we don't use those tables for selecting via bun's relations API anymore, so we should be able to just drop the tables.

[voigt]

I created a PR to tackle this.

However, looks like it's not only dropping the table. There are still some code paths referencing the tables:

• https://github.com/superseriousbusiness/gotosocial/blob/main/internal/db/bundb/status.go#L300
• https://github.com/superseriousbusiness/gotosocial/blob/main/internal/db/bundb/emoji.go#L81
• https://github.com/superseriousbusiness/gotosocial/blob/main/internal/gtsmodel/status.go#L40 (btw. what is m2m?)
• ...
• https://github.com/superseriousbusiness/gotosocial/blob/main/internal/db/bundb/account.go#L195
• https://github.com/superseriousbusiness/gotosocial/blob/main/internal/db/bundb/account.go#L228
• https://github.com/superseriousbusiness/gotosocial/blob/main/internal/db/bundb/emoji.go#L90
• https://github.com/superseriousbusiness/gotosocial/blob/main/internal/gtsmodel/account.go#L45

If you agree, I'd remove them as well.

[tsmethurst]

I'm gonna close this one now, since we've decided to keep some of those intermediary tables around, as they're actually useful for things other than just doing m2m relations.