[ci] Refactor "test.yml" into Reusable Workflow (#3459)

Change the monolithic test.yml Continuous Integration GitHub Action into a
reusable workflow that is called by a new "ci.yml" workflow.  The
check-tests/all_tests_passed are moved into "ci.yml" as are publishing and
deploy jobs.

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@sifive.com>