Bug 1706607 - Add prefs for the URL query string stripping. r=dimi

We add two prefs in this patch, including
'privacy.query_stripping.enabled' and
'privacy.query_stripping.strip_list'.

The pref 'privacy.query_stripping.enabled' is the general controller of
the URL query string stripping. And the pref
'privacy.query_stripping.strip_list' is the list of the query strings
that should be stripped from the URL.

Differential Revision: https://phabricator.services.mozilla.com/D113841

modules/libpref/init/StaticPrefList.yaml

@@ -10220,6 +10220,20 @@
   value: false
   mirror: always
 
+# The global switch to control the URL query sting stripping which strips query
+# parameters from loading URIs to prevent bounce (redirect) tracking.
+- name: privacy.query_stripping.enabled
+  type: RelaxedAtomicBool
+  value: false
+  mirror: always
+
+# The list which contains query parameters that are needed to be stripped from
+# URIs. The query parameters are separated by a space.
+- name: privacy.query_stripping.strip_list
+  type: String
+  value: ""
+  mirror: never
+
 #---------------------------------------------------------------------------
 # Prefs starting with "prompts."
 #---------------------------------------------------------------------------