[SDL 0154] Add SDL Core Daemon script

[theresalech]

Proposal: Add SDL Core Daemon script

This proposal is for the addition of a daemon script allowing simple control over the lifecycle of SDL Core. This script would allow users to easily start/restart/stop SDL Core in the background without needing to create their own scripts to manage this behavior, as is currently the case.

Review: smartdevicelink/sdl_evolution#444

[jacobkeeler]

Closing with the merge of #3417