Pull request: 4863 fix dhcp request

Merge in DNS/adguard-home from 4863-fix-dhcp-request to master

Closes #4863.

Squashed commit of the following:

commit f8872015e315eab3b2ce0249e552d12cbcf72f63
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Aug 30 20:34:35 2022 +0300

    dhcpd: imp code

commit b63c5d98c2055c3a3b76ff47737551840409f324
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Aug 30 20:19:22 2022 +0300

    dhcpd: fix deadlock

commit 5c03b54a86ab05efde9716faef60b84ecab01d19
Merge: f076cf8f 8733f55c
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Aug 30 19:12:27 2022 +0300

    Merge branch 'master' into 4863-fix-dhcp-request

commit f076cf8fc13944613b7127aac86ca78f68009f93
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Aug 30 19:08:04 2022 +0300

    dhcpd: imp code, names

commit a09540b6db6b86b80b8eb84c08187bfd9f960190
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Aug 30 17:28:39 2022 +0300

    dhcpd: imp code, docs

commit 38b12235509aaf55fa130f820213410b6b3022bb
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Aug 30 16:42:32 2022 +0300

    dhcpd: imp docs more

commit ff07c2f90f097754beb736fd5bd5cafc337ac65c
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Aug 30 16:41:42 2022 +0300

    dhcpd: fix docs

commit fafbc2ec2317f2320d8e1db167a1ae6c1c7c3790
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Aug 30 16:35:42 2022 +0300

    dhcpd: imp code

commit 9fe30190a7f125fd640b58e17661a4c33c078eba
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Aug 30 15:00:56 2022 +0300

    all: imp chlog

commit 1067fe95df5cb2252d1b9b70d2f3f8463997aea1
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Aug 30 14:54:03 2022 +0300

    dhcpd: log changes

commit 20de395c2bdcfb8e0554bb1c45385c15d617be65
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Aug 30 14:49:58 2022 +0300

    dhcpd: impl rfc 2131 for req

CHANGELOG.md

@@ -32,6 +32,7 @@ and this project adheres to
 
 ### Changed
 
+- The DHCPREQUEST handling is now closer to the [RFC 2131][rfc-2131] ([#4863]).
 - The internal DNS client, used to resolve hostnames of external clients and
   also during automatic updates, now respects the upstream mode settings for the
   main DNS client ([#4403]).
@@ -55,6 +56,9 @@ and this project adheres to
 [#4535]: https://github.com/AdguardTeam/AdGuardHome/issues/4535
 [#4745]: https://github.com/AdguardTeam/AdGuardHome/issues/4745
 [#4850]: https://github.com/AdguardTeam/AdGuardHome/issues/4850
+[#4863]: https://github.com/AdguardTeam/AdGuardHome/issues/4863
+
+[rfc-2131]: https://datatracker.ietf.org/doc/html/rfc2131