docs(refactor): Large refactor + additions + fixes

Consistency pass, formatting cleanup and fixes, introduce admonitions, add front-matter.

---

docs: Add front-matter

---

docs: Fix and format links

- Some links were invalid (eg files moved or renamed)
- Some were valid but had invalid section headers (content removed or migrated)
- Some use `http://` instead of `https://` when the website supports a secure connection.
- Some already used the `[name][reference]` convention but often with a number that wasn't as useful for maintenance.
- All referenced docs needed URLs replaced. Opted for the `[name][reference]` approach to group them all clearly at the bottom of the doc, especially with the relative URLs and in some cases many duplicate entries.
- All `tomav` references from the original repo prior to switch to an organization have been corrected.
- Minor cosmetic changes to the `name` part of the URL, such as for referencing issues to be consistent.
- Some small changes to text body, usually due to duplicate URL reference that was unnecessary (open relay, youtous)
- Switched other links to use the `[name][reference]` format when there was a large group of URLs such as wikipedia or kubernetes. Github repos that reference projects related to `docker-mailserver` also got placed here so they're noticed better by maintainers. This also helped quite a bit with `mermaid` external links that are very long.
- There was a Github Wiki supported syntax in use `[[name | link]]` for `fetchmail` page that isn't compatible by default with MkDocs (needs a plugin), converted to `[name][reference]` instead since it's a relative link.

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docs: Update commit link for LDAP override script

Logic moved to another file, keeping the permalink commit reference so it's unaffected by any changes in the file referenced in future.

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docs: Heading corrections

Consistency pass. Helps with the Table of Contents (top-right UI) aka Document Outline.
docs: codefence cleanup

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docs: misc cleanup

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docs: Add Admonitions

Switches `<details>` usage for collapsible admonitions (`???`) while other text content is switched to the visually more distinct admoniton (`!!!` or `???+`) style.

This does affect editor syntax highlighting a bit and markdown linting as it's custom non-standard markdown syntax.

docs/content/config/setup.sh.md

@@ -1,8 +1,14 @@
-[`setup.sh`](https://github.com/docker-mailserver/docker-mailserver/blob/master/setup.sh) is an administration script that helps with the most common tasks, including initial configuration. It is intented to be used from the host machine, _not_ from within your running container.
+---
+title: Your best friend setup.sh
+hide:
+  - toc # Hide Table of Contents for this page
+---
+
+[`setup.sh`][github-file-setupsh] is an administration script that helps with the most common tasks, including initial configuration. It is intented to be used from the host machine, _not_ from within your running container.
 
 The latest version of the script is included in the `docker-mailserver` repository. You may retrieve it at any time by running this command in your console:
 
-``` BASH
+```sh
 wget https://raw.githubusercontent.com/docker-mailserver/docker-mailserver/master/setup.sh
 chmod a+x ./setup.sh
 ```
@@ -11,7 +17,7 @@ chmod a+x ./setup.sh
 
 Run `./setup.sh -h` and you'll get some usage information:
 
-``` BASH
+```bash
 setup.sh Bootstrapping Script
 
 Usage: ./setup.sh [-i IMAGE_NAME] [-c CONTAINER_NAME] <subcommand> <subcommand> [args]
@@ -75,4 +81,6 @@ SUBCOMMANDS:
     ./setup.sh debug login <commands>
 
   help: Show this help dialogue
-```
+```
+
+[github-file-setupsh]: https://github.com/docker-mailserver/docker-mailserver/blob/master/setup.sh