Add option to use national flag of Belarus
Belarus has currently 2 flags:
- official red-green which is currently used in xkb plugin
- historical national flag: white-red-white which is accepted by the majority of the population. Sometimes this flag is also used with the symbol "Pahonia" on it - knight with a sword. https://commons.wikimedia.org/wiki/File:Alternative_Flag_of_Belarus-2.svg
I would like to add this flag to the plugin as a second option. Could you please suggest a better way of adding it?