Add option to create indexes, and don't do it while creating schema

[jeroarenas]

If indexes are created from the beginning, data loading on the postgres db will be very slow. It is better to load data first, and then create indexes once the data is ready. Two choices are given:

• Preferred: Create indexes on each table after ingesting all data relevant to that table
• Other: Create a new option in the menu to create indexes at the very end

[jeroarenas]

For the time being, I have modified create_schema to remove index creation. It should be placed somewhere else, after population of the tables.

I have also removed from that file the creation of the LEMAS table