Add relational extension property "sequence" to support FunctionMethod object type in latest Teiid

Teiid 10.x translator logic added a new extension property called "sequence" for an object type of FunctionMethod.

Designer's relational model does not have that object type, so need to add the property to the relational.mxd and add the logic to expose the property of procedure's isFunction == TRUE and import/export that value via -vdb.xml and DDL features.