cassini-[doc,config,distro,tests]: Add PARSEC support
Added parsec-service and parsec-tool support to Cassini stack.
Introduced a new DISTRO_FEATURE cassini-parsec
to conditionally enable/disable PARSEC support. Added simple e2e tests from parsec-tool as integration test for parsec-service.
Changelog: feature Signed-off-by: Devaraj Ranganna devaraj.ranganna@arm.com