JOSS paper could be simplified

Important

this issue only applies to the paper-joss branch from !210.

As can be seen in recent publications, e.g. https://joss.theoj.org/papers/10.21105/joss.08485 or https://joss.theoj.org/papers/10.21105/joss.09009, there are no details about project structure (dependencies, mirror repo, test procedure, etc.).

We could remove the following sections or subsections:

• Quality control
• Availability
• Contact and support bits at the end of the current Statement of need