S1ck Graph Versions Save

What's Changed

• Add adjacency list backed graph implementation by @s1ck in https://github.com/neo4j-labs/graph/pull/113
• Thread-safe edge mutation by @s1ck in https://github.com/neo4j-labs/graph/pull/114
• Improve Adjacency List build performance by @s1ck in https://github.com/neo4j-labs/graph/pull/115