Merge in DNS/dnsproxy from close-upstream-conf to master

Squashed commit of the following:

commit 69175c34643cb8e55e97bb0c2a56746730ff2c97
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Oct 25 17:23:12 2022 +0300

    proxy: add todo

commit d5d1996fecbd65ea109af3af7c2b913fd2248afd
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Oct 25 17:06:59 2022 +0300

    proxy: fix docs

commit d8156796c944b01633a635194c3fe52896361985
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Oct 25 17:05:04 2022 +0300

    proxy: close upstream conf beter