Add tslint rule for imports

[waltersajtos]

Is your feature request related to a problem? Please describe.
I think that it would be good to get a consistent order in the import for every file

Describe the solution you'd like
Implement the 'ordered-imports' rule in the tslint config.

[waltersajtos]

We need to discuss when we are implementing this if we want to do it. It will cause a lot of merge conflicts because we would have to update all the imports in every file.