Allow specifying middleware for individual and groups of Operations (Action, Query) on the server

[Martinsos]

If you want to execute some logic that is common for a group of Operations (and maybe also APIs), there is no simple way to do it -> we do have customMiddleware for APIs and api namespaces, but not for Operations or groups of Operations. You might want this to do some auth checks, maybe check the role of the user, or maybe inject some additional information that all of these need, ... .

So, what we want is enable users to provide middleware that executes for a group of Operations / APIs. Maybe we can specify this by grouping them somehow, or by specifying the route prefix (although for Operations, their route is implementation detail right now, so something would have to change there). We should of course consider if we can utilize existing expressjs functionality vs reimplementing too much of this on our own, what makes more sense.