Improve Github workflow

[denys-chura]

After 60 days of inactivity workflows with schedule trigger will be disabled by Github https://docs.github.com/en/actions/writing-workflows/choosing-when-your-workflow-runs/events-that-trigger-workflows#schedule. As it turns out, this workflow also will not be triggered by pull_request/push triggers which is not ideal. We can mitigate that by creating re-usable workflow and call it from two different workflows on triggered on schedule and another one triggered on pull_request/push.

Change list

• Update pull_request triggers types to only ones which correspond to code changes;
• Extract jobs from default.yml workflow to re-usable test.yml to be able to split default workflow to two workflow with different set of triggers - "schedule" and "pull_request/push"

Do not delete this PR branch untill https://github.com/django-stars/backend-skeleton/pull/86 is merged to main

[bulya]

In the context of this PR, we can also add a feature to cancel the currently running job or workflow in the same concurrency group. https://docs.github.com/en/actions/writing-workflows/workflow-syntax-for-github-actions#concurrency In the same way, as we want to add to the generated project's workflow - https://github.com/django-stars/backend-skeleton/pull/89/files#diff-6b6e5067e5f2be7f76884a405b3180738fad9fc44f11f63fbb019641426e03feR4-R6