Bug 444213: Initial version of SharedCodeService.

https://bugs.eclipse.org/bugs/show_bug.cgi?id=444213

Change-Id: I754cf70e5b3ae23527d388c7f2b29cc7885d681c
Reviewed-on: https://git.eclipse.org/r/38849
Tested-by: Hudson CI
Reviewed-by: Jeremie Bresson <jbr@bsiag.com>