Another fix for some potions not disabling

Adjusted how potion disable logic works to hopefully fix cases where some potions would have infinite uses

Fixed errors for clients on dedicated servers which caused very weird behavior for all potions

Added convars to control which potions are enabled
Added convars to tweak how the potions work

Added ability to force immortality potion to stay equipped while it is being used

Revert previous change

Updated Speed Potion logic to hopefully fix an issue where a player could get stuck with permanent super speed

Changed poison to not do poison damage by default due to the issues it causes

Added setting to change poison to use an alternate damage type to avoid poison overlays

Fixed potential errors in some potions when trying to end their effects when the owner was no longer valid