[FEATURE] PocketBase Collections Support in DrawDB

[jonm01]

Visualize PocketBase database schema directly in drawDB. Add support for PocketBase collections in drawDB, allowing users to connect to a PocketBase server or import a collections.json file.

Additional context:
PocketBase (https://pocketbase.io) is a popular open-source backend with an embedded SQLite database.

PocketBaseUML (https://github.com/pocketbase-uml/pocketbase-uml.github.io) generates UML diagrams.