Cleanup internal endpoints

[pcapriotti]

This moves internal endpoints to the Internal module hierarchy in wire-api, so that they are not included in the generated Swagger, and removes usages of servant-generic from Galley's internal API.

Checklist

• The PR Title explains the impact of the change.
• The PR description provides context as to why the change should occur and what the code contributes to that effect. This could also be a link to a JIRA ticket or a Github issue, if there is one.
• changelog.d contains the following bits of information (details):
  • A file with the changelog entry in one or more suitable sub-sections. The sub-sections are marked by directories inside changelog.d.

[fisx]

I suspect this will conflict with #2059. Not sure what to do about it, though.

[fisx]

please, no one-letter names :(

[pcapriotti]

Why are you picking on this particular one? The codebase is full of one-letter names. Even for this very purpose (see e.g. Galley.API.Teams.Features). I'm actually not sure what the problem is with one-letter names when they stand for very abstract things in a very limited scope (e.g. a single expression, like in this example). Also, the name that was there before isn't even correctly describing what the variable stands for (it's not a "feature name").

[mdimjasevic]

Overall this looks good.

I'm just curious: what is the motivation for removing internal endpoints from Swagger? Should we maybe put it into a different root/folder, but still have Swagger for internal endpoints?

[pcapriotti]

Overall this looks good.

I'm just curious: what is the motivation for removing internal endpoints from Swagger? Should we maybe put it into a different root/folder, but still have Swagger for internal endpoints?

Because the current swagger is supposed to present the API as visible from the outside (e.g. the Z-User header is not documented directly). Also, internal endpoints can overlap, and are only meaningful for a given service. For example, it would be nice to see a bunch of /i/status endpoints with no indication of which service they belong to.