[Feature Request] Manually declare a graph schema (avoid synchronization)

**Community Note**
* Please use a 👍 reaction to provide a +1/vote. This helps the community and maintainers prioritize this request.
* If you are interested in working on this issue or have submitted a pull request, please leave a comment.

**Graph Explorer Version (and Graph Database and Version used if applicable)**
All

**Is your feature request related to a problem? Please describe.**
Not all graph databases offer the ability to fetch a graph schema in a performant manner. Instead of forcing a user to perform a "Synchronization" upon connecting to a database, instead offer the ability for a user to define their graph schema with their connection configuration. This would avoid longer synchronization times on databases that rely on fetching schema-on-read via queries/

**Describe the solution you'd like**
In the connection configuration, allow a user to provide their graph schema via some form of definition file - JSON, YAML, etc.

**Additional context**
N/A