Add simple standalone example data

[fedarko]

We don't necessarily need a full tutorial or anything, but it would be nice to have an example in the README that uses data files included in this repository. Maybe setting these up as a subfolder in docs/moving-pictures (e.g. docs/moving-pictures/standalone-example-data/) would be easiest.

Newick and BIOM files are both pretty commonly used and clearly defined elsewhere, fortunately -- so I suspect the main "ambiguity" for many users will be in determining how the TSV metadata files should be formatted, since maybe some people would think that the samples should be columns or something. The easiest way to explain that is probably via example. (The main difference with the sample_metadata.tsv used in the repo right now is that the #q2:types row should be removed, as #499 points out.) Similarly, the skbio OrdinationResults format is probably unfamiliar to many people, so having an example of that would be nice.

This doesn't necessarily need to be the same thing as the moving pictures data, although if we did just reuse that then it'd be easy to "generalize" the tutorial to both standalone and QIIME 2 usage. (Although that would likely be another, less urgent, task.)

[fedarko]

"issue #500" hits different :pensive: