[TC-290] Add a way to select query string parameters to drop at edge

[limited]

for example input url ::

http://host/path?key1=something&key2=somethingelse&key3=foo
Want to set per delivery service which of the keys get dropped or used in cachekey and passed up (regex_remap case).

so config should be like::

keep:key2
or ::
drop: key1,key3

Author: Derek Gelinas
JIRA Link: https://issues.apache.org/jira/browse/TC-290

[mitchell852]

bumping this to a minor. @dg4prez if this is a major, can you reapply the major label and provide some examples of use cases that would require this behavior?