[api] transition to using IDs as primary key

[ioistired]

Would require a new version of the api, v1, unless we used different endpoints. Reason is snowflakes are valid emote names, so we wouldn't be able to auto detect whether the parameter is an emote or snowflake.

If done, perhaps add GET /emote/by-name/{name} which does a 301 redirect to /emote/{id}.
Or just advise users to use the /search/{query} endpoint and get the first match.