Prepare example models 1

[blairlyons]

• [x] https://github.com/simularium/simularium-website/issues/326
• [x] https://github.com/simularium/simulariumio/issues/40

Use Case

As a user of the Viewer website, I want to see example trajectories from Vivarium, that include PDB geometry, and from ME Johnson et al paper discussing when spatial simulation is needed.

Acceptance criteria

• .simularium file for Vivarium E coli is posted
• .simularium file(s) with PDB geometry are posted
• .simularium file(s) from ME Johnson et al are posted

[jsavieo]

@blairlyons and @jsavieo to work on paring this back