feat(docker): add GPU support and enhance installation scripts

- Introduced a new docker-compose.gpu.yml file to define GPU resource reservations for backend services.
- Updated .env.example to include GPU-related environment variables and usage instructions.
- Enhanced install.ps1 and install.sh scripts to support GPU variant selection and validation for GPU count.
- Improved error handling and user feedback for invalid GPU configurations.

docker/docker-compose.gpu.yml

@@ -0,0 +1,30 @@
+services:
+  backend:
+    deploy:
+      resources:
+        reservations:
+          devices:
+            - driver: ${SURFSENSE_GPU_DRIVER:-nvidia}
+              count: ${SURFSENSE_GPU_COUNT:-1}
+              capabilities:
+                - gpu
+
+  celery_worker:
+    deploy:
+      resources:
+        reservations:
+          devices:
+            - driver: ${SURFSENSE_GPU_DRIVER:-nvidia}
+              count: ${SURFSENSE_GPU_COUNT:-1}
+              capabilities:
+                - gpu
+
+  celery_beat:
+    deploy:
+      resources:
+        reservations:
+          devices:
+            - driver: ${SURFSENSE_GPU_DRIVER:-nvidia}
+              count: ${SURFSENSE_GPU_COUNT:-1}
+              capabilities:
+                - gpu