github workflows: automate registration in Jenkins

[samuelbernardolip]

Possible quick solution to bypass the requirement to register github cretentials in Jenkins
https://github.com/marketplace/actions/trigger-jenkins-multiple-jobs

With this action is possible to launch the jenkins job passing the github token, in this case provided by the user.
Seems a cleaner approach, also useful for dockerhub when using github as id provider.

Also mentioning here another action project to deploy a jenkins instance prepared to run maven jobs, an all in one approach that can be useful for developer independent builds:
https://github.com/marketplace/actions/jenkinsfile-runner-prepackaged