[CSM] Add flavour limits controlled by server (#5930)

* [CSM] Add flavour limits controlled by server

Server send flavour limits to client permitting to disable or limit some Lua calls

* Add limits for reading nodedefs and itemdefs

* flavour: Add lookup node limits

* Merge get_node_or_nil into get_node.

Sending fake node doesn't make sense in CSM, just return nil if node is not available for any reason

* Add node range customization when noderange flavour is enabled (default 8 nodes)

* Limit nodes range & disable chat message sending by default

* Bump protocol version

src/settings.cpp

@@ -398,6 +398,11 @@ s16 Settings::getS16(const std::string &name) const
 }
 
 
+u32 Settings::getU32(const std::string &name) const
+{
+	return (u32) stoi(get(name));
+}
+
 s32 Settings::getS32(const std::string &name) const
 {
 	return stoi(get(name));