Make issues for useful unimplemented_commands we want to port, cull the rest

[mitchmcdee]

As per title. Realistically I want to get rid of https://github.com/notmitchmcdee/uqcsbot/tree/master/unimplemented_commands, so we need to determine what is useful to port (which we should make an issue to track) and what can be culled.

[bradleysigma]

Remaining unimplemented_commands split into issues #459, #460, #461, #462, #463, #464, #465, #466, #467, #468 & #469.