build: add Prisma 7, PostgreSQL driver and @nestjs/config

Generate the Prisma client on postinstall. Jest now transpiles the ESM-only @nestjs/config and maps the .js imports of the generated Prisma client, in both the unit and e2e configurations.

test/jest-e2e.json

@@ -4,6 +4,20 @@
   "testEnvironment": "node",
   "testRegex": ".e2e-spec.ts$",
   "transform": {
-    "^.+\\.(t|j)s$": "ts-jest"
+    "^.+.ts$": "ts-jest",
+    "^.+.js$": [
+      "ts-jest",
+      {
+        "tsconfig": {
+          "allowJs": true,
+          "module": "commonjs",
+          "moduleResolution": "node"
+        }
+      }
+    ]
+  },
+  "transformIgnorePatterns": ["/node_modules/(?!@nestjs/config/)"],
+  "moduleNameMapper": {
+    "^(.{1,2}/.*).js$": "$1"
   }
 }