Pull request: 3172 fix mobileconfig

Merge in DNS/adguard-home from 3172-mobileconfig to master

Updates #3172.
Updates #2497.

Squashed commit of the following:

commit 30549ef4eda9d88f0738089e901492d7369caa25
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Tue Jun 1 21:00:17 2021 +0300

    all: log changes

commit 9b9429447430a8e5656b992c04c4a74606dc5f9f
Author: Ildar Kamalov <ik@adguard.com>
Date:   Tue Jun 1 17:56:59 2021 +0300

    client: always show port input

commit 6d6a0bdfaa849220a5ddb4a17502ab05379d7a1c
Merge: 13a3bffd 77946a7f
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Tue Jun 1 17:50:41 2021 +0300

    Merge branch 'master' into 3172-mobileconfig

commit 13a3bffd4dd6ccabf3d261f17b2c758a5c61eb9c
Author: Ildar Kamalov <ik@adguard.com>
Date:   Tue Jun 1 17:20:17 2021 +0300

    client: add port to mobile config form

commit f6abe0b6044572f3801c31b683e76f90c4a28487
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Mon May 31 19:43:37 2021 +0300

    home: imp cyclo

commit c304a0bacdca6f8b5ffd21f3d00c8244ea9e4e36
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Mon May 31 18:19:46 2021 +0300

    home: reduce allocs

commit 10a7678861079b710bb0ef14569c60a09612ec70
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Mon May 24 20:05:08 2021 +0300

    all: make the host parameter required

openapi/CHANGELOG.md

@@ -4,6 +4,12 @@
 
 ## v0.107: API changes
 
+### The parameter `"host"` in `GET /apple/*.mobileconfig` is now required.
+
+* The parameter `"host"` in `GET` requests for `/apple/doh.mobileconfig` and
+  `/apple/doh.mobileconfig` is now required to prevent unexpected server name's
+  value.
+
 ### The new field `"default_local_ptr_upstreams"` in `GET /control/dns_info`
 
 * The new optional field `"default_local_ptr_upstreams"` is the list of IP

openapi/openapi.yaml

@@ -1129,6 +1129,7 @@
         'example': 'example.org'
         'in': 'query'
         'name': 'host'
+        'required': true
         'schema':
           'type': 'string'
       - 'description': >
@@ -1163,6 +1164,7 @@
         'example': 'example.org'
         'in': 'query'
         'name': 'host'
+        'required': true
         'schema':
           'type': 'string'
       - 'description': >