Support graph algorithms

[Dtenwolde]

This issue will be used as a central place to gather graph algorithms that can/will be implemented in DuckPGQ (without sticking to a specific timeline). There are many graph algorithms, but there are probably too many to implement all of them. However, supporting a few would be a good start. We also have to see which algorithms can be efficiently executed using the CSR representation.

Path-finding:

• [x] BFS
• [ ] DFS (not likely)
• [x] Bellman-Ford
• [ ] Dijkstra's Algorithm - Wikipedia
• [ ] A Algorithm* - Wikipedia
• [ ] Floyd-Warshall Algorithm - Wikipedia
• [ ] Johnson's Algorithm - Wikipedia

Community Detection:

• [x] #138
• [ ] Leiden Algorithm - Leiden Algorithm
• [x] Local Clustering Coefficient
• [ ] Girvan-Newman Algorithm - Wikipedia
• [ ] ~~Label Propagation Algorithm - Wikipedia~~
• [ ] Louvain Method - Wikipedia

Centrality Measures:

• [x] #143
• [ ] Betweenness Centrality - Wikipedia
• [ ] Closeness Centrality - Wikipedia
• [ ] Eigenvector Centrality - Wikipedia
• [ ] Strongly Connected Components - Wikipedia
• [ ] Articulation Points and Bridges - Wikipedia
• [ ] 2-Edge-Connected Components - Wikipedia

Matching and Flow:

• [ ] Edmonds-Karp Algorithm - Wikipedia
• [ ] Hopcroft-Karp Algorithm - Wikipedia
• [ ] Blossom Algorithm - Wikipedia

Spectral Graph Theory:

• [ ] Spectral Clustering - Wikipedia
• [ ] Graph Laplacian - Wikipedia

Graph Embedding:

• [ ] Node2Vec - Wikipedia
• [ ] DeepWalk - Wikipedia

Miscellaneous:

• [ ] Random Walk - Wikipedia
• [ ] Graph Coloring - Wikipedia
• [ ] Minimum Spanning Tree (MST) - Wikipedia