[joss-review] Improve statement of need in docs

[zonca]

https://bayeseor.readthedocs.io/en/latest/index.html

has a good description of what the software does, can you add details about audience and possibly relation to other work?

Ref: https://joss.readthedocs.io/en/latest/review_criteria.html#a-statement-of-need

[jburba]

Hi @zonca , to clarify, would you like us to add these details to the statement of need in our JOSS paper or to the BayesEoR documentation?

[zonca]

documentation