updateAndBuild.action should have a REST API endpoint and/or be documented

The updateAndBuild.action URL in Bamboo is used to ask Bamboo to conditionally build. When using repository triggers, this is the only way to ensure that the build isn't run every time and instead respects the options laid out in plan branching and advanced repository configuration.

If one uses the build queue service, all options and restrictions are ignored, forcing a manual build. This is especially problematic for users using Bitbucket and OnDemand as this means every push to Bitbucket (which uses the queue API) will trigger the build, which costs users money using EC2, as it is the only way to build in Bamboo OnDemand.

This URL should either be changed/added to the REST API or documented well so that users can use it. This issue kind of depends on BAM-13699, which is linked.