Pull request: all: rename autohost_tld to local_domain_name

Merge in DNS/adguard-home-wiki from 2961-local-domain-name to master

Squashed commit of the following:

commit 54e0a08190660986518bed0fc62950ae788201e6
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Thu Apr 15 18:52:03 2021 +0300

    all: rename autohost_tld to local_domain_name

Configuration.md

@@ -231,10 +231,10 @@ Settings are stored in [YAML format](https://en.wikipedia.org/wiki/YAML), possib
     - `cache_time` — Safe Browsing, Safe Search, Parental Control cache TTL
     - `max_goroutines` — Max. number of parallel goroutines for processing incoming requests
     - `ipset` — List of domain-ipset_name associations for adding IP addresses of the specified domain names to an ipset list. Syntax: `DOMAIN[,DOMAIN].../IPSET_NAME[,IPSET_NAME]...`. IPv4 addresses are added to an ipset list with `ipv4` family, IPv6 addresses - to `ipv6` ipset list. ipset list must exist. This setting is supported on Linux only. This feature is similar to `--ipset` in dnsmasq.
-    - `autohost_tld` (**since v0.106.0**) — The top-level domain that AdGuard
+    - `local_domain_name` (**since v0.106.0**) — The domain name that AdGuard
       Home uses for known internal hosts.  The default value, which is also set
       when this value is empty, is `lan`.  So, if you have a machine called
-      `myhost` in your network, its automatic hostname will be `myhost.lan`.
+      `myhost` in your network, its hostname will be `myhost.lan`.
     - `resolve_clients` (**since v0.106.0**) - Enable/disable resolving clients'
       addresses by sending PTR requests.
 - `filters` — List of filters, each filter has the following values:

DHCP.md

@@ -116,5 +116,5 @@ the TLD is `lan`.  For example, if you have a machine called “workstation” i
 the network, and it sends a DHCP request with option 12 set to `workstation`,
 you can reach it over HTTP on the host `http://workstation.lan`.
 
-You can also set a custom TLD using the `dns.autohost_tld` field in the
-[configuration] file.
+You can also set a custom TLD or domain name using the `dns.local_domain_name`
+field in the [configuration] file.