Add reusable workflows for CI testing

[turkenf]

Description of your changes

This PR adds reusable workflows to be reused by official provider repositories for CI testing.

I have:

• Run make reviewable test to ensure this PR is ready for review.

How has this code been tested

Manually tested on turkenf/uptest and turkenf/azuread

[ytsarev]

That looks great and reusable. According to the description, you have already fully end-to-end tested on your forks. That's great!

Just in case I ran it through https://github.com/rhysd/actionlint and it's green apart from shellcheck error, but I don't think it make sense to quote the globally available special variable in this case

./provider-ci.yml:121:9: shellcheck reported issue in this script: SC2086:info:1:37: Double quote to prevent globbing and word splitting [shellcheck]
    |
121 |         run: echo "cache=$(make go.cachedir)" >> $GITHUB_OUTPUT

Additional advice for the future is to run this pipeline through https://app.stepsecurity.io/secureworkflow/ and adopt some of the security hardening. This tools was recommended by CNCF when my other project was going through CNCF security slam( we scored 100 eventually https://clomonitor.io/projects/cncf/k8gb )

Security hardening is a topic for another PR, so this one is good to merge, great job!

[turkenf]

Security hardening is a topic for another PR, so this one is good to merge, great job!

I opened an issue on your suggestion: #73
Thank you