Add SQL for the definition of (initial) tables and constraints

I will then update the definitions to account for modifications
applied in patches so far, before adding definitions for three
new tables for name aliases of authors, institutions and countries.
Add missing primary key constraint for new institutions table
Update schema in SQL to create the database

This is the latest schema, retrieved using `show tables`
and `show create table table_name` for each table.

These declarations combine fields and constraints, which
are not longer declared separately using `ALTER TABLE`.

Based on `show create table ...` output, I added the
`IF NOT EXISTS` clause and removed the configuration of
initial counter value for `AUTO_INCREMENT`, since the
intent of this script is to recreate an empty database.