Documentation needs to be more user friendly for the community

[jason-c-kwan]

To prepare for the Autometa v2 publication, which should reference this repo, the documentation needs to be cleaned up so that readers of that paper, and others of the community:

1. Know what this repository is, and what it is used for.
2. How to use it
3. How to add to and contribute to it.

I have not done a deep dive into this project yet, but it would also be useful to have instructions on:

4. How to get the reference data, including CAMI I and CAMI II.

[jason-c-kwan]

Also, it is not obvious within a few minutes of looking which binners and taxon profilers are supported already.