packaging: engine-service: allow service user customization

Change-Id: Ie71a3a56c77e29aea87b955dc82cd194e88c3582
Signed-off-by: Alon Bar-Lev <alonbl@redhat.com>
packaging: engine-service: remove %config from limits.d file

there is no sense in adding %config to conf.d file as it can
be overridden in a file with lower priority.

Change-Id: I5f0ebc414fa87f5e944e9d002373f3501638bfd2
Signed-off-by: Alon Bar-Lev <alonbl@redhat.com>
packaging: engine-service: systemd usage

Use features of systemd instead our own implementation.

1. detach from controlling terminal.
2. Change user/group.
3. stop service by intercepting signal.
4. set rlimit.

This makes it simpler for us, as only the start method of the
engine-service is actually used, in both systemd and openrc.

After this we can also modify the system-v to use the proper
/etc/init.d/function and use the pidfile for status and stop, so that
only start will be left in the service script.

The background mode is left only for system-v, but this is the only
feature required, other features are provided by the daemon function.

Change-Id: Ie02f0d44bbba7d1a7af6bcf6b808610e85b907c6
Signed-off-by: Alon Bar-Lev <alonbl@redhat.com>
packaging: engine-setup re-write using otopi

Change-Id: I4d5e3ac7927802326e324c9b98ada75b421638aa
Signed-off-by: Alon Bar-Lev <alonbl@redhat.com>
Signed-off-by: Sandro Bonazzola <sbonazzo@redhat.com>
Signed-off-by: Alex Lourie <alourie@redhat.com>