Flyway - Internal .sql files are no longer present and don't need to be added as substrate resource

[jaikiran]

As noted in #2326 (comment), the .sql files which were previously present within the flyway jar are no longer present in it and are instead inlined into various java files. The code in our Flyway extension which was adding these files are substrate resources is effectively a no-op now. This commit removes that code.

For verification, here's what 5.x of flyway had:

jar -tf .m2/repository/org/flywaydb/flyway-core/5.2.4/flyway-core-5.2.4.jar  | grep \\.sql

org/flywaydb/core/internal/database/redshift/createMetaDataTable.sql
org/flywaydb/core/internal/database/saphana/createMetaDataTable.sql
org/flywaydb/core/internal/database/hsqldb/createMetaDataTable.sql
org/flywaydb/core/internal/database/sqlite/createMetaDataTable.sql
org/flywaydb/core/internal/database/cockroachdb/createMetaDataTable.sql
org/flywaydb/core/internal/database/mysql/createMetaDataTable.sql
org/flywaydb/core/internal/database/oracle/createMetaDataTable.sql
org/flywaydb/core/internal/database/h2/createMetaDataTable.sql
org/flywaydb/core/internal/database/derby/createMetaDataTable.sql
org/flywaydb/core/internal/database/sybasease/createMetaDataTable.sql
org/flywaydb/core/internal/database/postgresql/createMetaDataTable.sql

6.0.6 (the version we now use) doesn't have those anymore:

jar -tf .m2/repository/org/flywaydb/flyway-core/6.0.6/flyway-core-6.0.6.jar  | grep \\.sql

returns empty.

[Sanne]

Awesome, thanks!

[gsmet]

Merged, thanks!