Support for editing the behavior annex action language #2132

Support for editing the behavior annex action language.

Add support for editing the behavior action block for transitions.

Editing action language blocks will be text based. An embedded Xtext editor will be integrated into the Eclipse Property view when using the OSATE graphical editor. This will allow editing without needing to transition into the text editor. This behavior is similar to the capabilities provided by other tools.
The Xtext editor will not be integrated into the diagram view of the graphical editor at this time. Depending on resource availability and technical feasibility, this can be reevaluated later on in the project.