Add ServiceName + ApplicationName based server map

[intr3p1d]

Pinpoint currently stores the statistical data required by servermap at the agentId level. (columnName includes agentId)
Bump this up to a larger unit, only use serviceName + applicationName, to speed up reading the serverMap data.
For now, (maybe from 3.0.0 to 3.1.0), we'll store "default" in serviceName and use it whenever serviceName (or serviceId, etc.) is updated.