[SHIRO-818] Return other status codes for AuthorizationExceptions.

[bmarwell]

• do not map the class AuthorizationException itself (for now).
  This exception is only thrown from the aop support (which might need to be changed to a subclass)
  and from Jdbc/Ldap-Realms. But those should lead to internal server errors, as
  internal code has thrown an exception.

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[fpapon]

LGTM

[bmarwell]

Changes:

• Added logging to Exception Mappers
• Reduced the test case a little by using CXF Frontend (thanks to Romain)
• Removed an exception subclass