app: resolve soft restart issues

Clear the API cache when closing to purge stale callbacks.  In addition,
explicitly delte the server object after the eventloop stops.

Signed-off-by:  Eric Callahan <arksine.code@gmail.com>

moonraker/app.py

@@ -307,6 +307,7 @@ class MoonrakerApp:
         if self.secure_server is not None:
             self.secure_server.stop()
             await self.secure_server.close_all_connections()
+        APIDefinition.reset_cache()
 
     def register_endpoint(
         self,

moonraker/common.py

@@ -265,6 +265,10 @@ class APIDefinition:
     def get_cache(cls) -> Dict[str, APIDefinition]:
         return cls._cache
 
+    @classmethod
+    def reset_cache(cls) -> None:
+        cls._cache.clear()
+
 class APITransport:
     @property
     def transport_type(self) -> TransportType:

moonraker/server.py

@@ -641,6 +641,7 @@ def main(from_package: bool = True) -> None:
         # it is ok to use a blocking sleep here
         time.sleep(.5)
         logging.info("Attempting Server Restart...")
+        del server
         event_loop.reset()
     event_loop.close()
     logging.info("Server Shutdown")