Adopt ColPrac

[oxinabox]

I propose we formally adopt ColPrac for this repo

we have 3 active maintainers, being myself, @quinnj and @fredrikekre
so I think we are in a position to do so.

https://github.com/SciML/ColPrac

What do folk think?
Its more or less what we do anyway, but written down

[quinnj]

I'm in favor!