/quote - general improvements

[Sidpatchy]

/quote is currently unfathomably inefficient. The initial work for this was implemented in 0d1b24d, but is yet to be completed.

Need to figure out if caching (up-to) 50,000 messages is:
A) Against Discord TOS, or
B) Going to nuke the bot.

Alternatively, if there is a better way to pull a random message out of a hat that doesn't involve loading 50,000 messages, I am very open to implementing that, however, as it stands this doesn't appear to be possible with the Discord API.

[Sidpatchy]

[Sidpatchy]

The code this issue initially referenced was removed in 8a7d1b7 & 9d84071

That was not a sane solution to this problem for the reasons noted in 8a7d1b7.

If no better solution is available it may just be better to remove this feature from the public instance.