Expand documentation

[XedinUnknown]

When I suggested this plugin to my team, they had the following questions, which I think are valid, but are not mentioned in the readme:

1. Does this plugin only work for a pre-defined list of packages?

   Just state that in the docs.

2. Which packages does it work for?

   Link to this list.

3. Which files will it remove?

   Explain that it knows which specific files to remove, in addition to these.

4. Can it also remove docs and tests from all other packages, at least by default?

   Just mention that it cannot. But this would be a nice feature.

5. Can I configure which files to include/exclude from removal, in addition to the pre-configured ones?

   Explain that this is not possible. But again, this is a feature that would be great to see.