Move category package one level up

The puzzle `927-285714a8` from #927 has to be resolved: 

https://github.com/php-coder/mystamps/blob/a00046daa4b5e51d30c625fcec7c4bddba234e47/src/main/java/ru/mystamps/web/feature/category/package-info.java#L1-L1

The puzzle was created by Slava Semushin on 13-Jun-19.