Add wg_easy

Thanks for taking the time to suggest an addition to awesome-sysadmin!

Please fill out information below (all fields are mandatory unless noted otherwise):

```yaml
# software name
name: "WireGuard Easy"
# URL of the software project's homepage
website_url: "https://github.com/wg-easy/wg-easy"
# URL where the full source code of the program can be downloaded
source_code_url: "https://github.com/wg-easy/wg-easy"
# description of what the software does, shorter than 250 characters, sentence case
description: "The easiest way to run WireGuard VPN + Web-based Admin UI."
# list of license identifiers, see https://github.com/awesome-foss/awesome-sysadmin-data/blob/master/licenses.yml for the full list of licenses
licenses:
- AGPL-3.0
# list of languages/platforms, see https://github.com/awesome-foss/awesome-sysadmin-data/tree/master/platforms for the full list of platforms
platforms:
- Docker
# list of tags (categories), see https://github.com/awesome-foss/awesome-sysadmin-data/tree/master/tags for the full list of tags
tags:
- VPN
# (optional, true/false, default false) whether the software depends on a third-party service outside the user's control
depends_3rdparty: false
# (optional) link to an interactive demo of the software
demo_url: "https://my.awesome.softwar.e/demo"
# (optional) link to a list of clients/addons/plugins/apps/bots... for the software
related_software_url: "https://my.awesome.softwar.e/apps"
```

To ensure your issue is dealt with swiftly, please check the following (check the boxes `[x]`):

- [x] Submit one item per issue. This eases reviewing and speeds up inclusion.
- [x] You have searched the repository for any relevant [issues](https://github.com/awesome-foss/awesome-sysadmin-data/issues) or [PRs](https://github.com/awesome-foss/awesome-sysadmin-data/pulls), including closed ones.
- [x] Any software you are adding is not already listed at any of [awesome-selfhosted](https://github.com/awesome-selfhosted/awesome-selfhosted), [dbdb.io](https://dbdb.io/browse).
- [x] Any software project you are adding to the list is actively maintained.
- [x] Any software project you are adding was first released more than 12 months ago.
- [x] Any software project you are adding has working installation instructions.

Review the repository's contribution format, then verify the WireGuard Easy details against https://github.com/wg-easy/wg-easy and the referenced licenses, platforms, and tags data. Done means the software entry is added with the supplied name, URLs, description, AGPL-3.0 license, Docker platform, and VPN tag.

Written by the indexing model from the issue text.