Add Generate UserSystem Command

                        
|Q            |A       |
|---          |---     |
|Bug Fix?     |no       |
|New Feature? |yes       |
|BC Breaks?   |no       |
|Deprecations?|no       |
|Tests Pass?  |not sure, no testing code so better hope for the best |
|Fixed Tickets|GH-1    |

Todo

- [x] test every format and db-driver (manually)
- [x] update documentation
- [x] update generator to generate events class

Functional tests are currently missing as this is very specialized coding, and not easily testable.