Change file_type to file_uri in v3 Release entity
Using https instead of http to avoid redirect

Maven deployment to geppetto-nexus.puppetlabs.com failed because the
server replied with redirect code 302. This was caused by use
of a http based URL. The server then replied with a redirect to
a https based URL. The deployer didn't handle that gracefully.
Fix "URL is not absolute" failure when using command line Geppetto

Running commands like "mvn forge:validate" without explictly setting
the forge.moduleroot resulted in error messages about a URL not
being absolute. This commit ensures that the default URL is made
absolute (relative to the current directory).