Naming consistency - fg-metric? or cloud-metrics?

[lee212]

It might be confusing to see both names fgmetric and cloud-metrics in source codes.
To make it simple, we would be better using a single name: cloudmetrics.

In the near future, we will update function/class/module naming to cloudmetrics.

Example for the change

from fgmetric... import ... => from cloudmetrics ... import ...
class FGMetric... -> class CloudMetrics...