[462355] refactor BPMN2Editor for use outside of an IDE

Splitting the BPMN2Editor into BPMN2Editor and DefaultBPMN2Editor where
the later is IDE independent.
Where possible use DefaultBPMN2Editor instead of BPMN2Editor to reduce
IDE dependencies.

Bug: https://bugs.eclipse.org/bugs/show_bug.cgi?id=462355
Signed-off-by: Flavio Donzé <flavio.donze@gmx.ch>
13 files changed