Set robot account expiration and recreate it when account is removed

[hanlins]

For a robot account, from a security standpoint, we should set an expiration for that account or at least rotate its credentials. As currently, we can't rotate robots' credentials/tokens in harbor itself, we should set an expiration date in the operator when creating the robot account as a future improvement. And by the nature of controller reconciliation logic, a new robot account should be created after the old one expires.

[hanlins]

For reference, the robot account is set to never expire.

	params := products.NewPostProjectsProjectIDRobotsParamsWithContext(c.context).
		WithTimeout(c.timeout).
		WithHTTPClient(c.insecureClient).
		WithProjectID(projectID).
		WithRobot(&models.RobotAccountCreate{
			Access: []*models.RobotAccountAccess{
				{
					Action:   "push",
					Resource: fmt.Sprintf("/project/%d/repository", projectID),
				},
			},
			Description: "automated by harbor automation operator",
			ExpiresAt:   -1, // never
			Name:        utils.RandomName("4k8s"),
		})