Remove "Slowdown Fungal Growth" mod

[RenechCDDA]

Summary

None

Purpose of change

The mod "Slowdown Fungal Growth" does not meet the criteria for our in-repo mods. It is a simple balance mod which changes one(1) creature in the game.

Its existence impairs development and whenever newer players ask about fungals growing raises questions about "Did you disable the default mod?" etc.

It clogs up the mod list. We have lots of really impactful, beautiful mods which offer entirely different gameplay and settings. This isn't one of them.

There's simply no reason for the mod to exist.

Describe the solution

Nix it. Obsolete the mod itself and mainline its effects. Add notes to the only content it changed explaining why things are the way they are, to carry us into a future with hopefully rebalanced fungals.

Describe alternatives you've considered

Well we could just delete the mod without mainlining it...

Testing

CI might need to be adjusted to account for it being obsolete. We'll see.

Additional context

[PatrikLundell]

I agree with the change, but what happens to existing games when the mod is removed?

Does marking the mod as obsolete cause it to be kept, dropped silently, in a way informing the player that the mod is obsolete, or will the game simply complain without an explanation?
If it's the third case it matters what the message looks like, as an unsuitable message may cause players to wonder what it happening and whether their game is broken.

[GuardianDll]

obsoleted mods are hidden from the mod menu, but preserved in the existing save file

[Karol1223]

I believe there now currently is support for straight up removing mods. Procyonae did it for some very old map mods if I recall.