Remove superfluous router dependency in UI5 Server

[LukasHeimann]

Is your feature request related to a problem? Please describe.

I'm currently debugging for SAP/karma-ui5#410 and found something strange that seems related to my original problem:

UI5 Server has express as a dependency, yet the CSP middleware uses the router dependency to build a middleware.

Describe the solution you'd like

The additional router dependency could easily be replaced with the express.Router middleware. This is a change in two lines of code which seems rather simple: https://github.com/SAP/ui5-server/blob/5f3f5797cbafac3b3c170951b20ee69b9326a48c/lib/middleware/csp.js#L76

Describe alternatives you've considered

Keep and mix two different router dependencies.

[matz3]

Thanks for your suggestion!
The express router relies on express-specific APIs on the req / res object. This conflicts with the karma-ui5 integration which is based on connect.
So without solving SAP/karma-ui5#410 by enhancing req/res, this change can't be made. And as this is not planned right now, I'm closing this as wontfix.