cassini-ci: Refactor CI jobs

These are the following changes:
* Add `ptest` job for corstone1000-mps3 to run parsec, k3s and
  containers tests
* Increase the timeout for `ptest` job for N1SDP enabling it to
  run the complete the test suite
* Add `sanity` job for N1SDP target

Signed-off-by: Vikas Katariya <vikas.katariya@arm.com>