Adds an assertion that the provided TOKEN has OAuth scope permissions for `repo`
as this is required for all merge attempts.
On failure, provides detailed error message with remediation steps for the user.
PR Close#37421
Moves the merge script from the components repository over
to the shared dev-infra package. The merge script has been
orginally built for all Angular repositories, but we just
kept it in the components repo temporarily to test it.
Since everything went well on the components side, we now
move the script over and integrate it into the dev-infra package.
PR Close#37138