change the database to allow storing of sbml units for species

persist/src/main/resources/db/migration/14.0.3/V14.0.1.20191016__substance_unit_complex_type.sql

+alter table element_table add column substance_unit_comlex_type_id integer;
+alter table element_table add foreign key (substance_unit_comlex_type_id) references sbml_unit_table(id);
+alter table element_table rename column substance_units to substance_unit_raw_type;