Support H2 database

This will entail:

1. Packaging the H2 jar together with OpenMRS
2. Correcting liquibase-core-schema, liquibase-core-data, liqbuibase-update-to-latest changsets to work with the H2 db.
3. Modifying the installation wizard to support H2 in the file storage mode.
4. Adding a java property 'installation.script' to provide connection details used by the installation wizard in simple and advanced mode.