Add `inferno-ml-server-types` package

[ngua]

Adds the inferno-ml-server-types package containing the API for a server that can evaluate Inferno scripts using ML primitives. There is no actual implementation of inferno-ml-server here

This and the whole Inferno ML infrastructure is still a WIP. However, a WIP implementation will need to be merged here in order to merge some WIPs in other repos. The following at least are not yet complete:

• making a polymorphic prelude for inferno-ml that doesn't depend on hasktorch (helpful for typechecking in cases where we can't use hasktorch)
• golden and other tests for the new types; however, since many of the types are polymorphic on something, it probably makes more sense to just add them in one of the places where inferno-ml-server or the bridge server are implemented
• a metrics endpoint for inferno-ml-server

I've also made a few changes to inferno-ml, which are listed in the changelog

[ngua]

Thanks @siddharth-krishna, I will address some of the comments/ideas as I keep working on this