Separete UI development from server one

[iampava]

Right now a FrontEnd developer cannot fully use the app without having access keys to services such as Amazon, Postmark, etc.

We should modify our app in such a way that it allows:

• core contributors / backend contributors to connect directly to these services via Access Keys/Tokens
• FrontEnd developers to connect to the development server: https://frontend-ro-dev.herokuapp.com/ and use any functionality without problems.

In other words, we need to untie Next JS from our app (if we can) and have a version running as a separate SPA.