[+BUGFIX] Fix and cleanup UriBuilder
This is mainly a refactoring of the UriBuilder.
But there are some slight changes in behavior too:
1. setRequest() now expects an instance of F3\FLOW3\MVC\Web\Request,
2. $this-arguments is not modified by any method apart
from setArguments() and reset()
3. setArgumentPrefix() (not part of the api) is removed,
the argument prefix is determined by the request instead