[bugfix] Rewrite existing OVAL umask accounts_umask_etc_profile.xml check to be super-compliant

Contains three patches (listing them in reverse order):

1) [bugfix] [shared/transforms/cpe_generate.py] Fix bug when generating cpe-oval file:

    This one is required to make cpe_generate.py to work properly with newly provided OVAL umask  template (see git log for more details).

2) [bugfix] [RHEL/6/input/checks/templates] Provide create_umask_checks.py template
    for generating (super-compliance) OVAL umask implementation.
  
  This one is the actual implementation of the OVAL umask template.

3) [bugfix] [RHEL/6, RHEL/7] accounts_umask_etc_profile OVAL check - start using the new OVAL umask template

   And this one applies that new OVAL umask template to existing accounts_umask_etc_profile.xml OVAL check. Tested both on RHEL6 & RHEL7, works as expected => moved to shared & equipped with test_attestations.

More existing umask checks to be rewritten into new OVAL template as soon as I have had chance to test them on both RHEL6 & RHEL7 & have confirmed they work as expected.

Please review.