Change groups table to used new long long int type for gid

It is now possible to do a proper order on gid, ie:
SELECT * FROM groups ORDER BY gid;

osquery/tables/specs/x/groups.table

@@ -1,6 +1,6 @@
 table_name("groups")
 schema([
-    Column(name="gid", type="std::string"),
+    Column(name="gid", type="long long int"),
     Column(name="name", type="std::string"),
 ])
 implementation("groups@genGroups")