cloud: Execute user-data scripts at the end of initialization

cloud: Execute user-data scripts at the end of initialization

This is useful when the user-data needs to reboot an instance.
Previously, some initialization did not happen which is now being done
first before the user-data script is being executed.

This gives users more flexibility about what they are doing in those
scripts.

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>