Moved VirtuosoDataSource to ODCS namespace.
DPURecord raw configuration changed from byte[] to String.

MySQL JDBC returns TEXT column type as byte[]. If entity attribute is also set
to byte[], EclipseLink presumes it is storing a serialized object. In such case
EclipseLink tries to deserialize it as a HEX string, which results in error.
Changing attribute type to String resolves this problem.
Added MySQL JDBC as a commons-app dependency.
Adjusted PipelineExecution status pulling DB query so it is DB-independent.
Adjusted schema.sql so it is prepared for conversion to MySQL dialect.
Added convertor for database dumps from Virtuoso to MySQL dialect.
Added MySQL database dumps.
Enabled MySQL data source.
Modified DPURecord#configValid to not-nullable column.
Added database platform property to configuration (Virtuoso / MySQL).
Implemented database platform switching based on configuration setting.
Fixed database platform initialization in SessionCustomizer.
Fixed filtering in Vaadin tables for MySQL.
Same connection pool is used for logging to DB and for persisting data.
Merge branch 'mysql'

Conflicts:
	db/virtuoso/rdbms/data.sql
	frontend/src/main/java/cz/cuni/mff/xrg/odcs/frontend/container/VaadinFilterTranslator.java