CI: Adopt moodle-plugin-ci usage in this repository

[joaop221]

Hi @weilai-irl, while applying new releases at my moodle internal repository, I've checked a unit test fail.

To minimize this problem, it could be conveniente adopt moodle-plugin-ci usage in public repository.

I'll try to make this implementation here, but I don't know if this is a relevant idea for this repository.

Regards, JP.

### Tasks
- [x] Validate idea
- [x] MOODLE_401_STABLE
- [x] MOODLE_402_STABLE
- [x] MOODLE_403_STABLE
- [x] MOODLE_404_STABLE

[joaop221]

POC:

• GHA File: https://github.com/joaop221/o365-moodle/blob/master/.github/workflows/main.yml
• Run: https://github.com/joaop221/o365-moodle/actions/runs/8422751668

Pipeline fails due to validation errors.

[weilai-irl]

Hi @joaop221

Thank you for making the recommendation. I agree this is a very good idea, and it should be the way to go.

I'll discuss with our team to make a formal decision on this. Considering the amount of errors, this may take some time. Please bare with us.

Regards, Lai

[joaop221]

Hi @weilai-irl

Apologies for not replying sooner. I've reviewed the implementation and am pleased that the foundational implementation is beneficial for the project.

Do you need help to reduce problems reported by moodle-plugin-ci?

[weilai-irl]

Hi @joaop221

No worries at all. We are busy with other tasks as well. The changes will be pushed live in the next release, which is expected before the end of September. I have seen the results of the checks and they look extremely helpful. I'm really looking forward for these changes.

Regarding the issues/warnings reported, we want to plan a short sprint to fix some (hopefully most) of them in a special release after these changes are released, and look after the rest in small chunks in future releases. We may need help then. Your help is very much appreciated.

Regards, Lai