Added new module data-mysql

A good starting point to review code is MysqlQueryTest.java
A good start to test the format is to upload molgenis-data-mysql/src/resources/example.xlsx

Open issues:
* TODO verify prevent sql injection in the queries

Closed issues:
* DONE implement MysqlRepository().update
* DONE fix counts of mrefs
* DONE fix the entities/forms (PK data type problems)
* DONE transaction support
* DONE integrate with importer
* DONE integrate with Data Explorer
* DONE date format (reset to original format)
* DONE default getIdAttribute() (removed to original without default)
* DONE some failing tests