Fix owner change with NFSv4 ACLs and cleanup related code paths

The problem being addressed here is that changing the owner changes the meaning of the special:owner and special:group entries in the NFSv4 ACL. Changing only the owner over SMB should not change the permissions, so write the NFSv4 ACL again, to have any "special" entries updated for the new mapping.

This includes the necessary changes for the NFSv4 ACL xattr module and GPFS. Other file system modules (AIX, ZFS) would need to pass in the previous ACL, but i did not have the means to verify those modules. The ACL chown behavior for those is still the same as before the patches.

Checklist

• Commits have Signed-off-by: with name/author being identical to the commit author
• (optional) This MR is just one part towards a larger feature.
• (optional, if backport required) Bugzilla bug filed and BUG: tag added
• Test suite updated with functionality tests
• Test suite updated with negative tests
• Documentation updated
• CI timeout is 3h or higher (see Settings/CICD/General pipelines/ Timeout)

Reviewer's checklist:

• There is a test suite reasonably covering new functionality or modifications
• Function naming, parameters, return values, types, etc., are consistent and according to README.Coding.md
• This feature/change has adequate documentation added
• No obvious mistakes in the code