fixes getTag with servePath option as url
adds tests for servePath as URL
Merge branch 'v3' of github.com:prcongithub/connect-assets into v3
Touch up test logic on CDN assertions.

Instead of dynamically generating a host (and using it), we can just use a static host (as this is more like how this feature will be actually used). We also don’t need to actually retrieve that URL at all during the test, since we’re only concerned that the URL is correctly generated.
Extract isAbsolutePath helper, touch up formatting

Extract a helper for determining if a path is absolute (we’ll probably want to tweak that for handling "//" paths soon).

Additionally, touched up the formatting and removed duplication when determining the asset path.