docs(chore): Normalize for consistency (#2206)

"Brief" summary/overview of changes. See the PR discussion or individual commits from the PR for more details.

---

Only applies to the `docs/content/**` content (_and `setup` command_). `target/` and `test/` can be normalized at a later date.

* Normalize to `example.com`

- Domains normalized to `example.com`: `mywebserver.com`, `myserver.tld`, `domain.com`, `domain.tld`, `mydomain.net`, `my-domain.tld`, `my-domain.com`, `example.org`, `whoami.com`.
- Alternative domains normalized to `not-example.com`: `otherdomain.com`, `otherdomain.tld`, `domain2.tld`, `mybackupmx.com`, `whoareyou.org`.
- Email addresses normalized to `admin@example.com` (in `ssl.md`): `foo@bar.com`, `yourcurrentemail@gmail.com`, `email@email.com`, `admin@domain.tld`.
- Email addresses normalized to `external-account@gmail.com`: `bill@gates321boom.com`, `external@gmail.com`, `myemail@gmail.com`, `real-email-address@external-domain.com`.
- **`faq.md`:** A FAQ entry title with `sample.domain.com` changed to `subdomain.example.com`.
- **`mail-fetchmail.md`:** Config examples with FQDNs for `imap`/`pop3` used `example.com` domain for a third-party, changed to `gmail.com` as more familiar third-party/external MTA.

* Normalize config volume path

- Normalizing local config path references to `./docker-data/dms/config/`: `./config/`, `config/`, \``config`\`, `/etc/` (_volume mount src path prefix_).
- Normalize DMS volume paths to `docker-data/dms/mail-{data,state,log}`: `./mail`, `./mail-state` `./data/mail`, `./data/state`, `./data/logs`, `./data/maildata`, `./data/mailstate`, `./data/maillogs`, (_dropped/converted data volumes: `maildata`, `mailstate`_).
- Other docker images also adopt the `docker-data/{service name}/` prefix.

* `ssl.md` - Use `dms/custom-certs` where appropriate.

* Apply normalizations to README and example `docker-compose.yml`

---

Common terms, sometimes interchangeably used or now invalid depending on context: `mail`, `mail container`, `mail server`, `mail-server`, `mailserver`,`docker-mailserver`, `Docker Mailserver`.

Rough transformations applied to most matches (_conditionally, depending on context_):

- 'Docker Mailserver' => '`docker-mailserver`'
- 'mail container' => '`docker-mailserver`' (_optionally retaining ' container'_)
- 'mail server' => 'mail-server' / '`docker-mailserver`'
- 'mail-server' => '`docker-mailserver`'
- 'mailserver' => 'mail-server' / '`docker-mailserver`'

Additionally I checked `docker run` (_plus `exec`, `logs`, etc, sub-commands_) and `docker-compose` commands. Often finding usage of `mail` instead of the expected `mailserver`

Additionally changes `mailserver` hostname in k8s to `mail` to align with other non-k8s examples.

---

* drive-by revisions

Mostly minor revisions or improvements to docs that aren't related to normalization effort.

docs/content/config/advanced/override-defaults/user-patches.md

@@ -4,20 +4,21 @@ title: 'Custom User Changes & Patches | Scripting'
 
 If you'd like to change, patch or alter files or behavior of `docker-mailserver`, you can use a script.
 
-In case you cloned this repository, you can copy the file `user-patches.sh.dist` under `config/` with `#!sh cp config/user-patches.sh.dist config/user-patches.sh` in order to create the `user-patches.sh` script. In case you are managing your directory structure yourself, create a `config/` directory and the `user-patches.sh` file yourself.
+In case you cloned this repository, you can copy the file [`user-patches.sh.dist` (_under `config/`_)][gh-file-userpatches] with `#!sh cp config/user-patches.sh.dist docker-data/dms/config/user-patches.sh` in order to create the `user-patches.sh` script.
+
+If you are managing your directory structure yourself, create a `docker-data/dms/config/` directory and add the `user-patches.sh` file yourself.
 
 ``` sh
-# 1. Either create the config/ directory yourself
-#    or let docker-mailserver create it on initial
-#    startup
-~/somewhere $ mkdir config && cd config
+# 1. Either create the docker-data/dms/config/ directory yourself
+#    or let docker-mailserver create it on initial startup
+/tmp $ mkdir -p docker-data/dms/config/ && cd docker-data/dms/config/
 
-# 2. Create the user-patches.sh and edit it
-~/somewhere/config $ touch user-patches.sh
-~/somewhere/config $ vi user-patches.sh
+# 2. Create the user-patches.sh file and edit it
+/tmp/docker-data/dms/config $ touch user-patches.sh
+/tmp/docker-data/dms/config $ nano user-patches.sh
 ```
 
-The contents could look like this
+The contents could look like this:
 
 ``` sh
 #! /bin/bash
@@ -32,10 +33,11 @@ $admin_maps_by_ccat{+CC_UNCHECKED} =  undef;
 1;  # ensure a defined return
 END
 
-...
 ```
 
 And you're done. The user patches script runs right before starting daemons. That means, all the other configuration is in place, so the script can make final adjustments.
 
 !!! note
     Many "patches" can already be done with the Docker Compose-/Stack-file. Adding hostnames to `/etc/hosts` is done with the `#!yaml extra_hosts:` section, `sysctl` commands can be managed with the `#!yaml sysctls:` section, etc.
+
+[gh-file-userpatches]: https://github.com/docker-mailserver/docker-mailserver/blob/master/config/user-patches.sh.dist