Add data center name filter to dataCenter gql query

[joneubank]

Adds the ability to retrieve an individual data center by ID.

Detailed Description

• [x] Add a function getDataCenterByShortName to the program service http client
• [x] Add an optional parameter for the dataCenter query to filter by data center short name.
• [x] Update the dataCenters resolver to accept the short name filter, and fetch a single data center when provided using the new http client function