Add section to README to describe configuration of an HA deployment.
Add section to README to describe configuration of an HA deployment.

[#86332520]

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