Support for Concordance DAT Delimiter/Separator

Sorry for the delayed response. This works great my only suggestion would be that when selecting "DAT" from the combo box.

Make the "Field separator" and "Quote character" default to Decimal 20 and 254 (as seen below)

These are the Concordance DAT file format specification defaults and will almost always be set to these. I would guess a less than 5% scenario where it would not be.

Originally posted by @fluxnull in https://github.com/sqlitebrowser/sqlitebrowser/issues/2012#issuecomment-770117325