Ability to import data directly from another database

[MrCsabaToth]

Currently SOEMPI can import data from flat files. See org/openhie/openempi/loader/file: AbstractFileLoader.java, ConfgurableFileLodaer.java, FileLoaderManager.java. The foundation of a DB loader already exists: org/openhie/openempi/loader/table: AbstractTableLoader.java, ConfigurableTableLoader.java. Subtasks:

• develop the code which can read data from the source database through JDBC.
• add the JDBC drivers for the supported databases (MySQL/MariaDB, Oracle, MS SQL, etc), right now the pom and the ear only contains PostgreSQL JDBC driver
• develop a wizard UI which walks the user through the import procedure: selecting DB server type, DB, table, configuring fields, etc