Add imageUrl to cf-mysql-template to make base64 image available in the metadata.
Add imageUrl to cf-mysql-template to make base64 image available in the
metadata.

[Finishes #63739446]

cloudfoundry/cf-mysql-release,ruanbinfeng/cf-mysql-release,ruanbinfeng/cf-mysql-release,krishna-mk/cf-mysql-release,cloudfoundry/cf-mysql-release,kbastani/cf-mysql-release,cloudfoundry/cf-mysql-release,CloudCredo/cf-mysql-release,cloudfoundry/cf-mysql-release,kbastani/cf-mysql-release,ruanbinfeng/cf-mysql-release,krishna-mk/cf-mysql-release,krishna-mk/cf-mysql-release,CloudCredo/cf-mysql-release,CloudCredo/cf-mysql-release,kbastani/cf-mysql-release,ruanbinfeng/cf-mysql-release