Allow custom LRs to have the CT selection menu displayed last instead of first

[azalty]

Allow custom LRs to have the CT selection menu displayed last instead of first in the case autostart isn't chosen.

Upon choosing a custom LR from the menu, it would call a plugin forward (or passed function) to let the custom plugin build their own menus, like a weapon selection menu, and then let the player chose their opponent through Hosties' natives.

Why?
Because custom LRs are currently very restricted and all Hosties core LRs are made like that: Ts choose all parameters first, then their choose their opponent.
Bringing this freedom will allow for more natural custom LR handling, and potentially more opportunities.