Add support for Jenkins 2.x

[gitmlynch]

The primary purpose of this effort was to add support for installing Jenkins 2.x. The key part of that support is bypassing the Jenkins 2.x setup wizard.

Along the way, I also added retries for several tasks including plugin installation/update where I was seeing transient task failures that worked on subsequent playbook executions.

Links relevant to the eis_ansible-jenkins role changes:

• https://github.com/EBSCOIS/eis_ansible-jenkins/tree/feature/plugin_config_support
• https://github.com/EBSCOIS/eis_ansible-jenkins/wiki/Purpose-and-Use-of-eis_ansible-jenkins

[gitmlynch]

Closing due to lack of attention. Probably obsolete now anyway.