Resolve internal id from timeseriesUrl in http attribute

[ChrisMalewski]

A timeseries of the series API can be uniquely identified through its direct REST endpoint.
E.g. http://www.fluggs.de/sos2/api/v1/timeseries/2/
We should add a function that creates an internal id from this link.
Then we can directly point to a timeseries graph by using that link (we do not know the internal id):

http://fluggs.wupperverband.de/swc/#/diagram?timespan=2017-01-23T23%3A59%3A59%2B01%3A00%2F2017-01-24T23%3A59%3A59%2B01%3A00&ts=**fluggs__2**

http://fluggs.wupperverband.de/swc/#/diagram?timespan=2017-01-23T23%3A59%3A59%2B01%3A00%2F2017-01-24T23%3A59%3A59%2B01%3A00&ts=**http://www.fluggs.de/sos2/api/v1/timeseries/2/**