Creates a new group.
none
DATA, 60 Bytes - the address of the new group.
// Request
curl -X POST --data '{"jsonrpc":"2.0","method":"shh_newGroup","params":[],"id":73}'
// Result
{
"id":1,
"jsonrpc": "2.0",
"result": "0xc65f283f440fd6cabea4dd7a2c807108f651b7135d1d6ca90931d93e97ab07fe42d923478ba2407d5b68aa497e4619ac10aa3b27726e1863c1fd9b570d99bbaf"
}