Create nll-Kanboard library

To be able to export tasks from Kanboard into static HTML, we need to be able to fetch them to begin with. CliffyPDA already has some existing code to fetch data from the Kanboard API, but we'll need to move it into a reusable library, and improve it's functionality.

The library is now available here.

It's a bit slow as the API is not as friendly as what the web app is using, for example, tags are not returned when getting a list of tasks, so they need to be fetched individually. It's good enough for now tho.

In the future maybe we can move to directly accessing the SQLite database for reads and only use the API for writes, which will speed things up a lot while keeping the same interface.