elasticbeanstalk: add more Options and make OptionSetting.of() package-private.
elasticbeanstalk: rename OptionSetting => Option and document.
elasticbeanstalk: make all Options enums UPPERCASE for consistency.
elasticbeanstalk: deprecate two Environment setters.

Environments should be configured from ConfigurationTemplates where possible.
elasticbeanstalk: create environments from config templates where possible.