(issue1764) Set upper-time and lower-time for time series axes This introduces new optional chart settings. Upper-time and lower-time. If they are present the client can show a date selection and they can be used for the domain axis in timeseries diagrams.

select.abflusstafel = \
    SELECT ABFLUSSTAFEL_NR, \
           ABFLUSSTAFEL_BEZ, \
           GUELTIG_VON, \
           GUELTIG_BIS, \
           PEGELNULLPUNKT, \
           AT.BFG_ID \
    FROM ABFLUSSTAFEL AT \
    WHERE MESSSTELLE_NR LIKE :number