Support systemd and rpmbuild

[hungrybirder]

Hi @tanelpoder I just added a spec file for supporting systemd.

Some features:

1. Start xcapture service and xcapture-restart.timer sevice after rpm -ivh oxtools or yum install -y 0xtools
2. Stop xcapture service and xcapture-restart.timer sevice after 0xtools has been removed.
3. xcapture-restart.timer sevice is a timer for cleaning up log files and restart xcapture process.

Please check it out. Thank you.

[tanelpoder]

Thanks for the PRs! I hope to review this within a week or so and merge with other changes & release.