Pull request: all: improve dnsrewrite handling

Merge in DNS/adguard-home from 2491-dnsrewrite-log to master

Closes #2491.

Squashed commit of the following:

commit bfe3cb599ed0a921285fb1a6ea27aaefdcc0d093
Merge: 95c5ffe43 15d8f979b
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Mon Dec 28 18:33:32 2020 +0300

    Merge branch 'master' into 2491-dnsrewrite-log

commit 95c5ffe4360b732556455f24b844dad27047e64b
Author: Artem Baskal <a.baskal@adguard.com>
Date:   Mon Dec 28 18:11:01 2020 +0300

    Add RewriteRule for client

commit b9096c8789009dac1838b542d3409fef54b59aa5
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Mon Dec 28 17:22:44 2020 +0300

    all: imp naming, docs

commit 4e00de0d613e4740451e4c8eb5a1de35a70a5896
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Mon Dec 28 17:16:35 2020 +0300

    all: imp naming, add todo

commit 67e4045f627a9569f382309705963640dcf3454a
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Mon Dec 28 16:53:00 2020 +0300

    all: improve dnsrewrite handling

openapi/CHANGELOG.md

@@ -6,7 +6,7 @@
 
 ### New `"reason"` in `GET /filtering/check_host` and `GET /querylog`
 
-* The new `DNSRewriteRule` reason is added to `GET /filtering/check_host` and
+* The new `RewriteRule` reason is added to `GET /filtering/check_host` and
   `GET /querylog`.
 
 * Also, the reason which was incorrectly documented as `"ReasonRewrite"` is now

openapi/openapi.yaml

@@ -1259,7 +1259,7 @@
           - 'FilteredBlockedService'
           - 'Rewrite'
           - 'RewriteEtcHosts'
-          - 'DNSRewriteRule'
+          - 'RewriteRule'
         'filter_id':
           'deprecated': true
           'description': >
@@ -1663,7 +1663,7 @@
           - 'FilteredBlockedService'
           - 'Rewrite'
           - 'RewriteEtcHosts'
-          - 'DNSRewriteRule'
+          - 'RewriteRule'
         'service_name':
           'type': 'string'
           'description': 'Set if reason=FilteredBlockedService'