Add OSRFcredentials class and test for DSL

[j-rivero]

This PR replaces the test.dsl in #1206 and checks the two main token that are going to be used for the osrfbuild user as discussed in #1206 (comment):

• OSRFBUILD_GITHUB_TOKEN: for git operations and pull requests
• OSRFBUILD_JENKINS_TOKEN: for authenticate into the server

The credential class also has an allowOsrfbuildToRunTheBuild that can restrict which projects can be build by the osrfbuild user when making remote calls.

Operations needs to be done in production:

• Generate a new OSRFBUILD_JENKINS_TOKEN for the osrfbuild user with the id of `
• Change the type of the OSRFBUILD_GITHUB_TOKEN or generate a new one and set it up as a usernamePassword with the ID github-osrfbuild-credentials

[j-rivero]

Working for both Jenkins API and Github token in

[j-rivero]

Going to merge to unblock other credential migration.