PR #8791 - use of BF-DFS in simple_cycles and all_simple_edge_paths

[Frank Bauernöppel]

Hi everybody, 

updated my PR #8791 with an unified implementation for enumerating simple paths and cycles with a length bound (BS-DFS).

All tests pass. Added a new file in algorithms, hope that's fine.

For additional tests see my repo  FrankBau/bsdfs: Bounded Scope Depth-First-Search for Finding Length Bound Simple Paths and Cycles in Directed Graphs

Happily awaiting your review comments

Frank