Refactor code structure and dependencies

- Remove unused files and modules
- Update submodule URL for epess-database
- Update DATABASE_URL in compose.yaml
- Update CI workflow to fetch submodules during checkout and fix GITHUB_TOKEN issue
- Enable strict mode in tsconfig.json
- Add UsersService and UsersResolver in users module
- Remove AppService and AppController
- Update main.ts to remove unused imports and log statement
- Add PrismaModule and PrismaService
- Add PrismaContextMiddleware
- Update GraphQL module to use schema and PrismaService
- Update package.json dependencies and devDependencies

tsconfig.json

@@ -16,6 +16,7 @@
     "noImplicitAny": true,
     "strictBindCallApply": true,
     "forceConsistentCasingInFileNames": true,
-    "noFallthroughCasesInSwitch": true
+    "noFallthroughCasesInSwitch": true,
+    "strict": true,
   }
 }