WebAdmin: Added more permission functions

```
Warn [20:25:03] LUA: attempt to compare two table values
Warn [20:25:03] Stack trace:
Warn [20:25:03]   [C](-1): sort
Warn [20:25:03]   Plugins/Core/web_players.lua(228): Handler
Warn [20:25:03]   Plugins/Core/web_players.lua(458): (no name)
Warn [20:25:03] Stack trace end
Warn [20:25:03] Error in plugin Core calling function <callback>()
```