Improve tournament creation process

[AlphaKretin]

Creating a tournament through a monolithic command is an issue. It forces a choice between either little customisation or a very complicated command. We could split it into multiple commands, where the initial creation command only specifies the name and you then build the description and other settings through a series of dedicated commands before opening it for registration.

[AlphaKretin]

One thing that needs to be customisable is choosing between OCG/TCG legality and various banlists

[AlphaKretin]

Another option that needs to be included is a participant cap

[AlphaKretin]

Another option is round length for the sake of a future timer feature. A distinction between live tournaments (~40-min round, counting down live and warning at like 10 minutes) and non-live (24-48 hr rounds, warning at 24/12/6 hours, no countdown).

[kevinlul]

Slash Commands fix this SO well