Support format variable metadata in test data

Adamig checks, like AD0041, require the use of variable format information. This metadata is available in xpt files. This information also needs to be available in the excel test data files

AC
- Test data loader recognizes an additional attribute of variable metadata, "format"
- Rule executor properly passes the variable format to the engine

We could overload the datatype row with the formats. We should be able to map format values to datatypes. This will prevent the need to go back and change all existing test data to have 5 metadata rows instead of 4.