Merge in GO/dnsproxy from 324-refactor-bootstrap to master

Updates #324.

Squashed commit of the following:

commit 9452c0b45a8602fd9371234c01ffda5009cf890f
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Wed Apr 12 14:50:04 2023 +0300

    fastest: imp docs

commit 3d7e941c
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Apr 11 20:11:59 2023 +0300

    bootstrap: fix test races

commit 2aee12a9
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Apr 11 19:58:42 2023 +0300

    bootstrap: fix logging

commit 716c08a8
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Apr 11 19:53:16 2023 +0300

    all: imp code, docs

commit 76dd0bdd
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Apr 11 16:28:47 2023 +0300

    upstream: clone req

commit b5ed3874
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Apr 11 16:20:30 2023 +0300

    fastip: fix helper upstream

commit 15e8329b
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Apr 11 16:09:19 2023 +0300

    upstream: imp code

commit 9897feae
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Mon Apr 10 17:24:27 2023 +0300

    bootstrap: fix doc

commit 3da08768
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Mon Apr 10 17:23:11 2023 +0300

    bootstrap: rm v6 tests

commit 5c819b4a
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Mon Apr 10 17:06:35 2023 +0300

    all: imp code, add tests

commit 442155aa
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Fri Apr 7 19:43:54 2023 +0300

    netutil: add doc

commit 6475e227
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Fri Apr 7 19:42:20 2023 +0300

    all: imp docs

commit 29732236
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Fri Apr 7 19:28:54 2023 +0300

    all: introduce bootstrap pkg