test suite / ci planning

[vsoch]

We need to, for the test suite:

• add a matrix of builds (based on flux-sched container bases). Note that not all of them (e.g, bookworm) have the reapi_cli.so shared library, and so we likely need to scope to the newer set that do (and then remove the flux-sched build from CI). test: adding testing matrix for os release matrix #4
• More standard go tests should be added for modules
• Would be nice to have some concept of a developer base image (e.g., pull and immediately have the full environment with bindings) but maybe that is not necessary. ci: add docker build environment and deploy #6
• Release cycle - first a manual push here, eventually a trigger to coincide with upstream ci: add automated release pipeline #5
• How to handle some number of backwards releases? (likely we can't and can only move forward for when reapi_cli.so is built).

The last bullet (testing modules) we will do as needed, as they are added. The main components of this issue are done, and we even have a first release. Not too shabby!