Move analytics.proto to its own repo and allow it to be a python dependency instead of checked in code

[bmbouter]

Right now the built analaytics.proto is built and then checked in to both this repo and pulpcore. It should instead be consumed as a python module that is received via PyPI.

To do this:

1. The analytics.proto should be moved to its own repo.
2. That repo should have CI that builds the protobuf python bindings
3. Publish the build bindings to PyPI via a date-based string

[bmbouter]

One question that came up was how to do this in development.

One idea I had was to have a developer who is making a change to analytics.proto (in its own repo after this change) compile it locally and install it as an editable python package. So both this repo and pulpcore would consume it as a python dependency only a locally built one for dev purposes. Also having the new repo where analytics.proto lives have a Makefile command would allow the CI and local devs to build it easily.

[bmbouter]

@mdellweg here's an idea ^

[mdellweg]

sounds rather complicated... but we should try it that way.