Metacat

refactor SystemMetadata creation into separate class from the MetacatHandler -- this will be shared by upgrade code and normal metacat api.

include all document revisions when generating "missing" system metadata
TODO: revision graph captured in obsoletes/obsoletedBy

When using ILock.lock(), get a lock on the string value of the Identifier, not the Identifier object itself. Hazelcast locking won't work otherwise.

Use the Hazelcast ILock mechanism to lock the system metadata identifier rather than using IMap.lock(pid).

simplify SystemMetadata generation -- will be done during Metacat upgrade for D1 features/support.

clean up populator; use IOUtils library to do string<->stream conversions

Set sessionid for clientVeiwBean when it handle a request.
Always set the order type to "allowFirst".

verify checksum when retrieving replica from another member node.
https://redmine.dataone.org/issues/1794

make sure to get/put system metadata to the HZ map instead of using IdentifierManager directly
verified changes for: https://redmine.dataone.org/issues/1999

match documentation for the MN.describe() header
https://redmine.dataone.org/issues/1904