API CHANGE:

Add a new action to the sysadm/users class: "groupmod"
This action allows for modifying a given group on the system

REQUIRED: "name"="<name of group to modify>"
and any one of these options is also required:
"users":["array of users"] (will set the list of users for this group)
"add_users":["array of users"] (will add the listed users to the current users)
"remove_users":["array of users"] (will remove the listed users from the current users)

Example API Request (JSON)
{
"id":"sample",
"namespace":"sysadm",
"name":"users",
"args":{
  "action":"groupmod",
  "name":"operator",
  "users":["user1","user2"]
  }
}

src/server/WebBackend.cpp

@@ -962,6 +962,9 @@ RestOutputStruct::ExitCode WebSocket::EvaluateSysadmUserRequest(bool allaccess,
     if(ok){ out->insert("result","success"); }
     else{ out->insert("error","Could not delete group"); }
 
+  }else if(action=="groupmod" && allaccess){
+    ok = sysadm::UserManager::modifyGroup(out, in_args.toObject() );
+
   }else if(action=="personacrypt_init"){
     qDebug() << "got PC init request:" << in_args << allaccess << user;
     bool go = true;