Title: #4974: CAless installation: set the perms on KDC cert file
### CAless installation: set the perms on KDC cert file
In CA less installation, the KDC certificate file does not have
the expected 644 permissions. As a consequence, WebUI login
The fix makes sure that the KDC cert file is saved with 644 perms.
### ipatests: check KDC cert permissions in CA less install
The KDC certificate file must be stored with 644 permissions.
Add a test checking the file permissions on server + replica.
To pull the PR as Git branch:
git remote add ghfreeipa https://github.com/freeipa/freeipa
git fetch ghfreeipa pull/4974/head:pr4974
git checkout pr4974