Common library (for back- and frontend)

[sjahreis]

Is your feature request related to a problem? Please describe.
A lot of code has to be duplicated as it is required in back- and frontend.

Describe the solution you'd like
Create a common multiplatform lib to share code between back- and frontend (see module commonin ktorbase https://github.com/linked-planet/ktorbase/tree/master/common)

[weickmanna]

@sjahreis solved by the OpenAPI generated code?
It's not yet part of the template ... would need some more example code

[sjahreis]

@weickmanna Yes this issue is solved by the generated code. I think we should add an example backend route and generate the code for it.