diagrams: clean up unused diagrams

- delete old ecore, entity diagrams
- remove folder structure
- delete dogen modeling diagrams as they are quite bit-rotten
config: move mock settings factory into config
engine: rename generator to engine (1/2)

- rename directories
engine: rename generator to engine (2/2)

- create types folder and move all files into it
- update namespaces, etc
engine: create model for engine