[mod] move some code from webapp module to webutils module (no functional change)

Over the years the webapp module became more and more a mess.  To improve the
modulaization a little this patch moves some implementations from the webapp
module to webutils module.

HINT: this patch brings non functional change

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

tests/unit/test_webapp.py

@@ -69,7 +69,7 @@ class ViewsTestCase(SearxTestCase):
                 infoboxes=[],
                 unresponsive_engines=set(),
                 results=test_results,
-                results_number=lambda: 3,
+                number_of_results=3,
                 results_length=lambda: len(test_results),
                 get_timings=lambda: timings,
                 redirect_url=None,