Low: Tools: crm: add shadow management to the configure level (improve usage)

Now users should be able to do stuff like:

crm(live)configure# ... do some changes ...

User wants to save it for future reference, i.e. not to the live
config:

crm(live)configure# cib new test1
INFO: test1 shadow CIB created
crm(test1)configure# commit

Mercurial revision: e8976462d43f6c40c313b99a3062064106577637