DATAJPA-623 - Fixed package cycles accidentally introduced.

Moved JpaEntityMetadata and DefaultJpaEntityMetadata to query package to avoid a cyclic dependency to it. Jpa21Utils now also resides in the query package as the util package must not depend on other project packages.

Updated the Sonargraph architecture description by adding new architectural artifacts for mapping, the CDI support and utilities. Defined allowed dependencies more strictly to detect architecture violations more aggressively.