[BUG] plugins should list cugraph/igraph compute/layout parameter options

[lmeyerov]

Describe the bug

All the (compute|layout)_(cugraph|igraph) methods support different built-in algorithms, which are explicitly lists in variables like https://github.com/graphistry/pygraphistry/blob/master/graphistry/plugins/cugraph.py#L167

However, the docs do not expose & link those, so users can't know which to call

The lists should be exposed, and the corresponding method docs should link to those lists