Add more MonoidK based folds

[BalmungSan]

I am opening this before adding tests and docs to get feedback and see if it is a worth-it addition or not; or even to confirm this doesn't exist already 😅

I found myself needing foldSequenceK today having a List[Resource[IO, HttpRoutes[IO]] and wanting to get back a Resource[IO, HttpRoutes[IO]] in an easy way.

[armanbilge]

Wait, is this foldMapM?

cats/core/src/main/scala/cats/Foldable.scala

Lines 545 to 546 in 14286c9

	def foldMapM[G[_], A, B](fa: F[A])(f: A => G[B])(implicit G: Monad[G], B: Monoid[B]): G[B] =
	foldM(fa, B.empty)((b, a) => G.map(f(a))(B.combine(b, _)))

[BalmungSan]

@armanbilge oh lol, you are right. So we were only missing the "friends", right?
Since I originally needed the most derived one (foldSequenceK) I traced back and started from scratch.

Although, I should have realized it, since I first thought of calling foldTraverseK like foldMapMK but thought that name was very confusing and decided to do the parallel with Traverse, also I was still thinking of using Applicative at that moment.

[BalmungSan]

Okay, after Arman realized I was reimplementing the wheel with the "traverse" ones.
I just added the "sequence" ones, and changed the name to be consistent... but, being totally honest, I dislike all of them, as well as the M vs A variants, those should be internal optimizations but I understand that was probably not a known idea by the time.
And I especially dislike that foldM takes the usual "fold" parameters instead of being like combineAll, but foldMK doesn't.

Actually, I just realized we are missing something combineAllM, and a foldA version that takes the usual "fold" parameters.