[REQ] Support ```useTags``` config option for java client code generation

Created by: eyalrin

Is your feature request related to a problem? Please describe.

I don't want users of my java client library to need to use different API classes to work with my service.

Describe the solution you'd like

Currently in Spring Code Generation there is an option to enable the useTags config option to control whether to generate different API classes for each tag/group or not. I would like this to be supported in the Java Client Generator as well so my customers can use a single API class (this setting should be independent form the Spring Generator since in the server code I still want this separation).

Describe alternatives you've considered

I thought of not using tags at all in my OpenAPI configuration but that make my server code less organized since all paths will need to be implemented in a single class (Since a single API class is generated in that case).