Add a 5 second delay between swarm registration attempts

src/Tgstation.Server.Host/Components/InstanceManager.cs

@@ -565,6 +565,9 @@ namespace Tgstation.Server.Host.Components
 
 				if (registrationResult == SwarmRegistrationResult.VersionMismatch)
 					throw new InvalidOperationException("Swarm controller's TGS version does not match our own!");
+
+				if (registrationResult != SwarmRegistrationResult.Success)
+					await asyncDelayer.Delay(TimeSpan.FromSeconds(5), cancellationToken);
 			}
 			while (registrationResult != SwarmRegistrationResult.Success && !cancellationToken.IsCancellationRequested);
 		}

src/Tgstation.Server.Host/Swarm/SwarmService.cs

@@ -821,6 +821,8 @@ namespace Tgstation.Server.Host.Swarm
 					logger.LogError("Swarm re-registration failed, controller's TGS version has changed!");
 					break;
 				}
+
+				await asyncDelayer.Delay(TimeSpan.FromSeconds(5), cancellationToken);
 			}
 
 			// we could do something here... but what?