[bugfix] [RHEL/6, RHEL/7] accounts_umask_etc_profile OVAL check - start using the new OVAL umask template

Testing report:

Checked & confirmed on both of RHEL6 & RHEL7 the proposed change works as expected (=>
moved to shared & equipped with test_attestations). More existing umask checks to be
rewritten to use the new template as soon as they have been tested & confirmed for work.