Write a JS server to handle metric data requests and other CDM queries via REST API.

[atheurer]

A not complete list of requests:

get-metrics:
input: period,source,type,breakout,filter,resolution (1 or more of these)
output: 1 or more data-series
get-result-summary
input: 1 or more run IDs
output: result-summary
get-iterations
input: tags, params, run-ids
output: iteration ids
get-samples:
input: iteration-id
output: sample-ids
get-sample-summary:
input: 1 or more iterations
output: min/mean/max/stddev
get-primary-period:
input: iteration-id
output: primary period id
get-primary-metric:
input: iteration-id
output: primary metric

[atheurer]

get-metrics completed with #149