Add a configuration to disable history for all projects in group

[tchikh411]

Is your feature request related to a problem? Please describe.
We have around 50 projects for which we do not want History and annotation. Because projects are added/removed frequently, it is difficult to maintain the readonly.xml configuration file for each project.

Describe the solution you'd like
OpenGrok already support groups. I think we should be able to configure the projects at the group level. I am only focusing on History and annotation but the idea extends to other configurations as well.

[vladak]

Makes sense. It should be possible to trickle down various configuration properties from group to project level and in the end repository level.