Allow requesting secrets by a different name

There are some cases, such as the artifact upload job, where the job can
take a dict parameter and where it could be advantageous to allow other
people to re-use the job but passing in their own local secret data by
supplying variables to a variant. However, currently secrets carry with
them a name, which is used as the variable name in ansible.

Make a secret in a job config be able to be given as a string or a
dict. In the dict case, the name of the secret and the name it should be
added to ansible as are required. This allows someone to have a named
secret but to pass it to a job under a different name.

Change-Id: I27a82c6ee1cf7399353509f98a0a52536ebbc19a
6 files changed