[OM] Remove Map and Tuple support.

[mikeurbach]

We have long deprecated and removed these from FIRRTL, so unless you emit OM dialect directly from a different frontend, there is no way to make use of these. And if you do have a frontend that emits the OM dialect directly, I would highly encourage you to instead make sure of Class, Object, and List to achieve the same goals. This is what Chisel does.

So, given these are redundant, mostly dead code, we should clean them up. I started on this long ago in a branch here: mikeurbach/om-map-cleanup. I had to pause because I ended up finding some internal users of these features.