[Proposal] New version of the dar-server as part of the "dar-backend-suite"

[ghost]

Hello,

I have created a new version of the dar-server.

It is a koa.js application which can read/write Dars from filesystem as well as from a MongoDB database.

The new dar-server should be backward-compatible with the current implementation, however I'm not a 100% sure.

The dar-server is furthermore part of a "dar-backend-suite" (didn't came up with a better name yet).

The dar-backend-suite is a collection of packages which a developer can use to create backends for Dar-based client applications. Every package constitutes an npm packge in it's own right and can be added to a project as a dependency. All in all the developer can pick and choose those packages he needs. Furthermore, the division of the different components into separate packages makes the code easier to understand and fosters code reuse.

Since the dar-server is part of this suite I didn't issue a pull request. If you like the new version of the dar-server as well as the approach taken with the dar-backend-suite maybe a new repository could be created within the "substance-workspace".

Best regards, Matthias