CSIT-1186: Add srv6 NDRPDR suites

CSIT-1186: Add srv6 NDRPDR suites

Delete the corresponding ndrpdrdisc suites.

MRR suites are also edited,
to make them less different from NDRPDR suites.

Now, there is a script to re-generate testcases of selected suites.
For that, resources/libraries/python/autogen is created,
with Regenerator holding the most of script logic.

The script looks at files matching a glob expression,
reuses a "prolog", but overwites test cases with the default template
and hardcoded set of testcase arguments.

Also, handling of overhead size has been simplified,
using new keyword Get Max Rate And Jumbo And Handle Multi Seg.

Default value for search timeout is increased to 12 minutes
to make timeout failures less frequent.

Change-Id: I394ad61f262b3078e5ca719034b15ada48987ee0
Signed-off-by: Vratko Polak <vrpolak@cisco.com>