remove irrelevant old JavaDoc from a long bygone era in northbound.api

remove irrelevant old JavaDoc from a long bygone era in northbound.api

and some other minor clean up like:

* make all Logger constants private
* move constants to beginning of class
* remove wrong empty lines, add required empty lines
* made some package local fields private
* remove clearly un-used fields

Change-Id: I0b087aae2dc35470e1d006675aa6f9c080d3de3f
Signed-off-by: Michael Vorburger <vorburger@redhat.com>