[webapp] Add bwtester auto-path switching and path colors in tests

[mwfarb]

@FR4NK-W mentioned awhile back it would be useful to alter the continuous run of bwtester to automatically switch known paths to obtain and graph bandwidth results over all paths. This would require some visual clue on the results to note which path was used for any given point on the graph. This might simply be done with a number noting the path number and hops, rather than the current mbps. So path 2, 4 hops might show "2 (4)" over the data point.

This would provide a quick way to know how paths in general are performing. In the tooltip over the data point, the list of interfaces IA text could be colored to match the ISD in the Paths tab. Better, if there is time, a simple linear version of the Paths graph could be drawn in the tooltip in place of text.