move IndexEvent into metacat-common. Perparation for Metacat responding to events and writing them to a persistent store. https://projects.ecoinformatics.org/ecoinfo/issues/5944
refactor IndexEventLog a bit to simplify type/action information. prep for serializing IndexEvent objects to Metacat. https://projects.ecoinformatics.org/ecoinfo/issues/5944
use an independent ISet<SystemMetadata> structure to communicate objects that should be indexed by metacat-index. https://projects.ecoinformatics.org/ecoinfo/issues/5943
The returned ISet should be Identifier.
Add method to get identifier set.
Add two static methods to get the SystemMetadata and data object InputStream for the specified id.
Put the waiting mechanism for the hazelcast at the first place.
Add a class to get distributed maps such as the system metadata map.