At the moment the MMV error handling works only "by accident":
- if an validation failure is found then the remaining initialization of authentication manager and persistence is skipped.
- attempting to go to the login causes a null pointer exception
- this exception is caught and then the MMV thrown
This also raises an issue for implementations of - say - the ThemeProvider that want to make database queries, eg via Settings service. The todoapp does this.
So, instead, we should always do the complete initialization even if there is a metamodel validation exception, but then intercept any such exceptions and route the MmvErrorPage thereafter.