Cascade close-out

Implement the option to close-out/announce requests and cascade the
status change to all resubmission children for the request.

For this there is a new view which allows the ReqMgr service
to construct the resubmission tree starting from a "original" request.

Usage:

\<reqmgrHost\>/reqMgr/closeout?requestName=\<rootRequest\>&cascade=True
\<reqmgrHost\>/reqMgr/announce?requestName=\<rootRequest\>&cascade=True
Fixes #4477