[feature] Circuit Breaker

This contains 1/2 of the circuit breaker. The change here is that if we mint more than the max supply of rune, burn some rune from the reserve to restore the supply at 500m.

The second part is pausing opening of loans in this scenario.

Code Walkthrough https://www.youtube.com/watch?v=e6gZ77DdMrc

x/thorchain/keeper/v1/keeper.go

@@ -410,12 +410,15 @@ func (k KVStore) MintToModule(ctx cosmos.Context, module string, coin common.Coi
 				if err := k.SendFromModuleToModule(ctx, ReserveName, ModuleName, common.NewCoins(burn)); err != nil {
 					ctx.Logger().Error("fail to move coins during circuit breaker", "error", err)
 					return err
-				} else {
-					err := k.BurnFromModule(ctx, ModuleName, burn)
-					if err != nil {
-						ctx.Logger().Error("fail to burn coins during circuit breaker", "error", err)
-						return err
-					}
+				}
+				err := k.BurnFromModule(ctx, ModuleName, burn)
+				if err != nil {
+					ctx.Logger().Error("fail to burn coins during circuit breaker", "error", err)
+					return err
+				}
+				burnEvt := NewEventMintBurn(BurnSupplyType, burn.Asset.Native(), burn.Amount, "circuit_breaker")
+				if err := mgr.EventMgr().EmitEvent(ctx, burnEvt); err != nil {
+					ctx.Logger().Error("fail to emit burn event", "error", err)
 				}
 			}
 		}