add ann's cool taxa associated via pathways network from the paper

[d-callan]

there is a cool network diagram here where all nodes are taxa, arranged in a circle, and there is an edge between two taxa if they are both correlated w at least one of the same pathways. any taxa correlated w at least one pathway has a node, so some nodes have no edges if there are no shared pathways w other taxa. its very cool, and gives a sense for the size and level of activity of a microbial community, though reading too much into any of the specific edges, etc is probably over-interpretting things. anywho, id love to make it easier to draw these. thatd probably mean:

1. adding a dedicated widget here
2. adding some sort of option to the shiny app which type of network to draw in the case where two data.tables are provided, and which table should be nodes vs edges in the case of the new widget
3. finding a name for this type of diagram
4. probably some work in the MicrobiomeDB R package also, to add a param to correlationNetwork or something. that could obvi be done separately, w a new issue made for that.