Split build-test-publish job

[fdcastel]

Proposed fix for #29.

[fdcastel]

As mentioned in #29, we should separate the "build-test" step from the "publish" step.

A good example of this can be seen in this recently merged PR:

• It passed in the official repository.
• It failed in the fork.

Forks should be able to build and run the tests for the project, but never attempt to publish it.

[fdcastel]

New fork-friendly workflows.

CI Workflow

• Triggered on all pushes and pull requests;
• Executes on all repositories (including forks);
• Performs build and test tasks.

Publish Workflow

• Triggered only by pushes to the master branch of the official repository and once weekly;
• Runs exclusively on the official repository;
• Executes build, test, and publish tasks.

All workflows support manual triggering via dispatch.

[fdcastel]

Rebased with latest master.

[fdcastel]

Rebased with the latest master.