feat: Add category label nodes and BELONGS_TO relationships

[ferdeleong]

Add category label nodes to the current graph, and connect already existing amenities label nodes to them through BELONGS_TO relationship.

Add test cases to:

• Guarantee the successful creation of category nodes based on the categories found on the current amenity_dataset.csv
• Guarantee the successful creation of BELONGS_TO relationships, one per amenity node based on their category field on the current amenity_dataset.csv

[conventional-commit-lint-gcf[bot]]

🤖 I detect that the PR title and the commit message differ and there's only one commit. To use the PR title for the commit history, you can use Github's automerge feature with squashing, or use automerge label. Good luck human!

-- conventional-commit-lint bot https://conventionalcommits.org/