[FEATURE] command to dump IDs of users that match pattern

[eepykate]

linked with #305, shouldn't be too hard to do the other if one is made, would just like one that doesn't instantly ban the users (ie the pattern might be a bit fuzzy and you wanna avoid false positives)

mod gives patterns, bot gets ids that match, and prints them

example patterns:

• joined between 2 time periods
• account was made between 2 time periods
• has X-Y amount of joins
• has X-Y amount of non-join messages
• is current member (or has left)
• has non-default pfp
• username (regex)

you should be able to use as many or as few of these as you want.

[eepykate]

might be a good idea to print that non-id info too instead of just using it to filter.

[elkowar]

We could look at some embedded Scripting lang (Lua or some more well suited query lang) then pipe a dump of all user data through a query provided in the command. Figuring out some sexy command api for this otherwise seems difficult, but just relying on existing stuff would be pretty basic I reckon.