Re-add .ModField.Type to TableExtractor

Added lines pertaining to ModFieldType (Datetime or Revision) so that
this argument is read from Excel config and passed correctly to
Qvc.IncrementalSetup.

Note: Use of Datetime and Revision in CAPS/Normal cases had caused a
bug: the config file examples are CAPS, and for safety, this value was
also converted to UPPER in the script. However, this data was itself
used as part of a variable name through $-constructs, where the
variables used Normal case.

This solution skips the uppercase-conversion of the script, however this
also requires the values in the config file to be Normal case. A better
solution may be to allow any case in the config file, convert to UPPER
and then change the $-expanded variable names instead.