Add new "Hospital / Healthcare Management" template

Hi Team

I noticed that DrawDB includes blog, e-commerce, HR, banking, library, and university schemas, but there is no _**Hospital / Healthcare Management template**_ yet. This is one of the most commonly used schemas in DBMS courses and real-world projects.

I would love to contribute this template. It would include tables like **patients, doctors, appointments, medical_records, departments, rooms, admissions, and billing.**

I believe this would be a valuable addition because:

Healthcare systems are a very popular use case

Many students and developers search for hospital schemas

It fits well with the template collection style and complexity

Please let me know if it's okay to proceed — I would be happy to open a PR