Reflect the filters in the URL for the series view
Whenever we filter on the patch view, the filters are reflected in the current URL (window.location) which makes them shareable and bookmarkable. E.g.: https://patchwork.freedesktop.org/project/intel-gfx/patches/?submitter=5895
The same is not true for series view (e.g. https://patchwork.freedesktop.org/project/intel-gfx/series/).
The used filtering mechanism seems to be different and UX is inconsistent. Let's fix that!