fix: Correct Cobbler installation script bugs
fix: Correct Cobbler installation script bugs

Modify file paths used during Cobbler install.
Fix regex used to remove lines from Apache2 configuration.
Add quotes around 'SECRET_KEY' python string.
Fix line breaks in 'KICKSTART_DONE' snippet.
Correct 'authorized_keys' file permissions.

Change-Id: I448c960aa3b6c4f5a4f7f1b4e8ad11c4ad5f4c93

open-power-ref-design-toolkit/cluster-genesis,open-power-ref-design-toolkit/cluster-genesis