[batch] Separate closed and open projects on billing limits page

[jigold]

Fixes #13205

Possible billing project states are defined in the database schema:

CREATE TABLE IF NOT EXISTS `billing_projects` (
  `name` VARCHAR(100) NOT NULL,
  `name_cs` VARCHAR(100) NOT NULL COLLATE utf8mb4_0900_as_cs,
  `status` ENUM('open', 'closed', 'deleted') NOT NULL DEFAULT 'open',
  `limit` DOUBLE DEFAULT NULL,
  `msec_mcpu` BIGINT DEFAULT 0,
  PRIMARY KEY (`name`)
) ENGINE = InnoDB;
CREATE INDEX `billing_project_status` ON `billing_projects` (`status`);
CREATE UNIQUE INDEX `billing_project_name_cs` ON `billing_projects` (`name_cs`);
CREATE INDEX `billing_project_name_cs_status` ON `billing_projects` (`name_cs`, `status`);

[iris-garden]

LGTM! We could use a Jinja2 macro to reduce code duplication in the template, but considering we want to revamp the frontend anyway, I don't think that needs to happen right now.