More efficient timeseries sql source structure

[sebastian-peter]

The current implementation relies on retrieving timeseries meta information from the timeseries table name. This means that for each timeseries uuid, the according table name is queried in SqlTimeSeriesMappingSource#getTimeSeriesMetaInformation. This is also not easily improved upon by using joins on table meta information.

Solution: Adding TimeSeriesTypeSource, which maps time series uuid to column scheme. From there, in a second step, tables structures can be adapted in #545.