feat: docker and swagger docs setup

feat: course-to-teacher - many-to-one relationship setup

feat: one-to-one relationship setup for course and course material

feat: student entity setup with custom repository methods and test cases

feat: code cleanup - setup for starter template

Merge branch 'basic_auth'

feat: exception handler added for department

feat: department CRUD added

feat: employee controller added

feat: JWT security implementation done

feat: basic JWT auth setup initialized

feat: book CRUD added

feat: springboot API setup with PostgreSQL