Truncation of text fields in the DWH on MySQL (#655886)

When using a MySQL database for the data warehouse, the transfer can fail due to the row size limit if a field group contains several text fields to be transferred. To avoid this problem, the values of data fields of the type Text (string) are now truncated. By default, only the first 512 characters of the field values are written to the DWH database.

The number of characters to be transferred can be adapted by adding the property cmrf.mysql.truncate.string with the desired value to the start command of the CMRF.