Automatically generate temp certificate

[rjrudin]

The code in the build.gradle file for the ssl-project shows how to generate a temp certificate. It's not easy to know this is required. And the Admin UI magically "fixes" this by automatically generating a temp certificate when the app server is saved, even without any changes.

Arguably, the Manage API should be doing the same thing. In the absence of that, I think ml-gradle should either do this automatically, or it should support a property to allow a user to easily do this - e.g. mlGenerateTempCertificate-templateId1,host1,templateId2,host2,etc.