Add Omega Server DSL methods: subsystem_entity? and cosmos_entity?

To be removed from manufactured/rjr/events, specs updated
Remove TODO comment
Split manu events rjr methods into seperate modules + helpers

Specs updated to reflect new module layout
Use Server DSL *_entity? methods in manu::subscribe_to

Removes methods from Manufactured::RJR module.

Also defines Manufactured::RJR#subscribable_entity? and updates
subscribe_to and remove_callbacks methods to use instead of
subsystem_entity?

Specs updated to test new / changed functionality
Split manufactured/rjr/move into seperate modules

No functional changes, code is more concise & easier to
maintain

Specs updated to reflect new layout
Split omega/client/mixins into seperate modules

Trackable mixin is still relatively large so should be refactored
beyond this at some point. Also while specs still work those
should be split up along module lines as well