feat: add graceful shutdown endpoint for UVM API server and update documentation

uvm/server.py

@@ -35,6 +35,7 @@ def create_api(application: Application | None = None, *, host: str | None = Non
         ) from error
 
     from .routers.health import router as health_router
+    from .routers.exit import router as exit_router
     from .routers.installation import router as installation_router
     from .routers.vms import router as vms_router
     from .routers.diagnostics import router as diagnostics_router
@@ -55,6 +56,7 @@ def create_api(application: Application | None = None, *, host: str | None = Non
         )
 
     api.include_router(health_router)
+    api.include_router(exit_router)
     api.include_router(installation_router)
     api.include_router(vms_router)
     api.include_router(diagnostics_router)
@@ -91,7 +93,10 @@ def run_server(application: Application, *, host: str, port: int) -> None:
     if settings.api_tls_cert is not None:
         options["ssl_certfile"] = str(settings.api_tls_cert)
         options["ssl_keyfile"] = str(settings.api_tls_key)
-    uvicorn.run(create_api(application, host=host), **options)
+    api = create_api(application, host=host)
+    server = uvicorn.Server(uvicorn.Config(api, **options))
+    api.state.uvicorn_server = server
+    server.run()
 
 
 def _is_loopback_host(host: str) -> bool: