API: Add /v1/health endpoint (#178)

* Add healthcheck

- localhost only /healthcheck endpoint
- cURL healthcheck in docker compose file

* Update Healthcheck Response

- change endpoint to /health
- remove localhost restriction
- add docstring

* move healthcheck definition to top of the file

- make the healthcheck show up first in the openAPI spec

* Tree: Format

docker/docker-compose.yml

@@ -8,6 +8,11 @@ services:
         - DO_PULL=true
     ports:
       - "5000:5000"
+    healthcheck:
+      test: ["CMD", "curl", "-f", "http://127.0.0.1:5000/health"]
+      interval: 30s
+      timeout: 10s
+      retries: 3
     environment:
       - NAME=TabbyAPI
       - NVIDIA_VISIBLE_DEVICES=all