Create dummy jobs only for MR into other branches.

for endpoints expecting none

for endpoints expecting payload

add error response json schema

add response schema and link in documentation

add response schema and link in documentation

reset FORCE_... variables to default

The previous approach to use rules:changes with push events is error prone (see https://docs.gitlab.com/ee/ci/jobs/job_control.html#use-onlychanges-without-pipelines-for-merge-requests)

read pid only once

run test as nobody