Add Feature-Policy header

[0pdd]

The puzzle 1161-69decc53 from #1161 has to be resolved:

mystamps/src/main/java/ru/mystamps/web/support/spring/security/SecurityConfig.java

Line 165 in e9eb623

// @todo #1161 Add Feature-Policy header

The puzzle was created by Slava Semushin on 20-Dec-20.

[php-coder]

Details: https://docs.spring.io/spring-security/site/docs/5.1.x/reference/html/default-security-headers-2.html#webflux-headers-feature