Add support for passing a charm/bundle id as a deploy-target query parameter

You can now add a query parameter `deploy-target` with the value a charm or bundle id to the url when loading the GUI to automatically deploy the charm or bundle to the environment.
The api only accepts requests in the format `bundle/foo/5/bar` for bundles and `precise/foo` for the charms. This seems like an inconsistency in the API but maybe that's fixed in v4?