The webhook "workflowJob" pass the labels the job needs to the controller, who in turns search for them in its RunnerDeployment / RunnerSet. The current implementation ignore the search for `self-hosted` if this is the only label, however if multiple labels are found the `self-hosted` label must be declared explicitely or the RD / RS will not be selected for the autoscaling.
This PR fixes the behavior by ignoring this label, and add documentation on this webhook for the other labels that will still require an explicit declaration (OS and architecture).
The exception should be temporary, ideally the labels implicitely created (self-hosted, OS, architecture) should be searchable alongside the explicitly declared labels.
code tested, work with `["self-hosted"]` and `["self-hosted","anotherLabel"]`
Fixes#951