Add support for spring-data

[hohwille]

Already from the beginning we had tough discussions about spring-boot as you can read in #2.
However things have changed meanwhile:

• multiple projects have used spring-data with success in production (so its also solid https://github.com/oasp/oasp4j/wiki/architecture#key-principles)
• simplicity of spring-data (less code, etc.)
• ability to go beyond RDBMS (NoSQL support)
• having things together that belong together (e.g. @Query annotation compared to named queries in XML files and QueryConstants).
• With Java8 and spring-data you can use default methods to implement dynamic queries (even with QueryDSL).

Therefore we want to make spring-data first class citizen of OASP4J but of course will continue to support our DAO approach as well (so no-one will be forced to migrate). We will only move the DAO stuff to a new module (see #616).

[hohwille]

Done with PR #627