Update tutorial / FAQ / troubleshooting / pitfalls doc to clarify filtering behavior

[mfisher87]

This is a fairly frequent question, so we must not have good enough docs on this. I think we should include a clear explanation and example of filtering (and clarify that filtering does not include subsetting) in our README.

• Filter earthaccess data with cloud coverage #445
• help with search_data() method #470

Note that this is different from this ticket, which is about doing post-selection filtering after results are returned: #428

[JessicaS11]

I've seen some great DAAC-generated visuals on the search/filter vs subsetting thing (e.g. this one). I know the visuals were super helpful for understanding the difference when I was getting into this work (and the spatial example is a great mental model for all filter vs subset types).

[mfisher87]

💯 Yes! I'd love to have a larger version of that image with just the comparison at the bottom!