[JENKINS-66740] Fix credentials permissions checks

[Dohbedoh]

Fixes JENKINS-66740 / https://github.com/Blazemeter/blazemeter-jenkins-plugin/issues/89.

• Use @AncestorInPath and AccessControlled to do a smart check based on the context
• Remove the jelly part that was preventing from creating also other types of credentials.

[Dohbedoh]

ping @dnyanesh-nagre-blazerunner