Format errors better for CLI (#552)

* Start making errors easier to read for Table based CLI UI.

* Add TODO about reporting "update_mask" related errors.

internal/cmd/commands/authmethods/authmethod.go

@@ -175,8 +175,8 @@ func (c *Command) Run(args []string) int {
 		plural = "auth methods"
 	}
 	if err != nil {
-		if api.AsServerError(err) != nil {
-			c.UI.Error(fmt.Sprintf("Error from controller when performing %s on %s: %s", c.Func, plural, err.Error()))
+		if apiErr := api.AsServerError(err); apiErr != nil {
+			c.UI.Error(fmt.Sprintf("Error from controller when performing %s on %s: %s", c.Func, plural, base.PrintApiError(apiErr)))
 			return 1
 		}
 		c.UI.Error(fmt.Sprintf("Error trying to %s %s: %s", c.Func, plural, err.Error()))