Fix NPE when no action can be parsed from the URL

Fix NPE when no action can be parsed from the URL

Renames `static final` variables according to convention to be in all
upper case. That makes it easier to see that in an `equals` comparison
the final variable should come first as it will not trigger a NPE.

Also strip parameters from the URL when extracting the repository
name from it. Parameters can not be part of a repository name, and
this way an empty repository name can be detected.

Fixes #1092