Add options to affect health refill from E-Tank pickups

[Kewlan]

• Disabled: No health is refilled.
• Vanilla: Standard behaviour.
• Full: Reserves are also refilled.

Disabled	Full

[blkerby]

I reworded the option, trying to move away from negatively-worded options like "Disable refill", since "Disable: No" can be harder to parse. Wording it as two options "Vanilla" and "Disabled" also leaves open the possibility of a third option in the future, where we might make ETanks refill reserve energy.

I applied this rewording at the surface in the UI, but would you mind applying it consistently to the internal variable names? Instead of a boolean, let's use an enum in the server code, e.g. ETankRefill (similar to AreaAssignment or WallJump).