Package tidy up

[lucapirolo]

Changes Made

1. Refactoring Types to config Package:

   • Moved Bookmarks type and related code into the config package.
   • Relocated TransactionConfig and SessionConfig to the config package.
   • Transferred AccessMode to the config package.

2. Updating References:

   • Updated all previous references from neo4j. to config. to reflect the new locations of these types.

3. Introducing Type Aliases for Backward Compatibility:

   • Introduced type aliases in the Neo4j package for each moved type to ensure backward compatibility.

[StephenCathcart]

@lucapirolo just letting you know I've not forgotten about this package tidy up! I'll be finishing up reviewing this soon and update the PR afterwards. Thanks again for the large contribution 👍