DURACLOUD-1150: Add REST API endpoints for total count, size and files in snapshots

[nwoodward]

*This PR adds new REST API endpoints for 1) total snapshots counts, 2) total snapshots sizes in bytes, and 3) total snapshot files based on a given search criteria. The search criteria are host, storeId, or status.

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JIRA Ticket: https://duracloud.atlassian.net/browse/DURACLOUD-1150

How should this be tested?

• Build and install (push to local maven repository the duracloud-1150 branch of DuraCloud (DURACLOUD-1150: Add REST API endpoints for total size and files in snapshots duracloud#148)
• Build and deploy locally this branch of the Bridge.
• Have 1+ snapshots in the Bridge
• Go to the endpoints for the new counts:
  • https://localhost:8080/snapshot/total/count
  • https://localhost:8080/snapshot/total/size
  • https://localhost:8080/snapshot/total/files

Additional Notes:

As mentioned in the test instructions this PR depends on another PR in the DuraCloud repository that contains the Bridge result classes for these new endpoints.

Interested parties

@duracloud/committers

[bbranan]

This looks great and works as expected, thanks @nwoodward!