Give server lib files less verbose names

[justinkambic]

It was noted in a recent PR that we are calling files by fairly verbose names. We can probably do away with some of these longer naming conventions, as they were created to follow a paradigm that we have largely dropped from our codebase.

Examples are things like elasticsearch_monitor_states_adapter, associated adapter_types files. We could rename these to monitor_states and types respectively, and coupling the file name with its directory name should be descriptive enough to convey the same information.

[shahzad31]

This is essentially duplicate of #131