Implement simple cycle search Python binding

[GenieTim]

Closes #804; here, the output is determined by the corresponding parameter.

[GenieTim]

The both option for the output will be requested in a separate PR that can be discussed individually, as it involves more than this function.

[szhorvat]

I would suggest using simply min and max for the parameter names. This will be consistent with cliques(), https://python.igraph.org/en/stable/api/igraph.GraphBase.html#cliques, which is another function with lower and upper limits on the objects returned.

[szhorvat]

@ntamas Could you please have a look at this when you get the time? This is very valuable functionality.

[szhorvat]

@ntamas Do you have any other concerns about this one (other than the comment I made above)?

[ntamas]

@ntamas Do you have any other concerns about this one (other than the comment I made above)?

Nope, no other concerns, but what you pointed out needs to be addressed.

[szhorvat]

Shall we merge this?