* INT-4574: JDBC: Add NOT NULL for primary keys
JIRA: https://jira.spring.io/browse/INT-4574
Some RDBMS don't allow have nullable columns for primary keys
* Add NOT NULL for all the columns involved in primary keys
**Cherry-pick to 4.3.x**
* * Include index generation into the `schema.sql.vpp`
* * Remove redundant blank line from generated scripts
* * Fix INT_CHANNEL_MESSAGE primary generation
# Conflicts:
# spring-integration-jdbc/src/main/resources/org/springframework/integration/jdbc/schema-mysql.sql
# spring-integration-jdbc/src/main/resources/org/springframework/integration/jdbc/schema-oracle.sql
# spring-integration-jdbc/src/main/sql/schema.sql.vpp
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