Feature/chimera quotient search

[jackraymond]

Expanded functionality to support Chimera and Pegasus quotient search alongside Zephyr (already implement).

Some refactorization of functions.

Expansion of the example to plot results, and use quotient search over a defect (rather than fully yielded) lattice.

[jackraymond]

TO DO:

• Example is failing for some seeds. Seems to be related to casting numpy integers to/from regular integers within tuples (can fix).
• Instead of using (m,t) and casting to (m,m,t) and (m,) respectively for Pegasus and Chimera, it might be tidier to use either a shape tuple for the graph [e.g. the output of qpu.properties['topology']['shape']] == first ordered parameters for graph generators and other graph-family specific functions]
• The zephyr example doesn't show the rails nicely due to too many overlapping edges, edges can be reordered so blue is plotted on top.