ci: Add ptest support for corstone1000-fvp

The ptest is split for nightly/weekly and Merge request runs:
The intention is to only run short-duration tests for each
merge request raised and longer tests for nightly/weekly
* `Merge request` run includes:
  user-accounts-integration-tests, container-engine-integration-tests,
  k3s-integration-tests and parsec-simple-e2e-tests
* nightly/weekly run includes:
  psa-arch-tests and all tests from `Merge request` run

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