Migrate SQLDIFF to liquibase changesets

The Current implementation of Patient Flags uses SQLDIFF to deploy tables relevant to It. Some tables are UTF8 and others are not. Its complex to cotroll versions in SQLDIFF implementation than in liquibase. The Current implemenation is causing migration issues whenever there is a change. It is importing to migrate the module to use liquibase changesets from the SQLDIFF which are currently being used.

Implemenation Critera
Must have all the SQL statement from sqldiff.xml file to liqubase statements into the liquibase.xml file.

Testing Critea
SQLDIFF File will not have any statement left that creates or changes the database
The following tables must be created when the module is deployed:
patientflags_displaypoint
patientflags_flag
patientflags_flag_tag
patientflags_priority
patientflags_tag
patientflags_tag_displayPoint
patientflags_tag_role

The source code is at https://github.com/openmrs/openmrs-module-patientflags