Add Outline to VPN

[alifa98]

Thank you for taking the time to work on a PR for Awesome-Sysadmin!

To ensure your PR is dealt with swiftly please check the following:

• [x] Your additions are Free software
• [x] Software your are submitting is not your own, unless you have a healthy ecosystem with a few contributors (which aren't your sock puppet accounts).
• [x] Format your submission as follows, where Demo and Clients are optional. Do not add a duplicate Source code link if it is the same as the main link. Keep the short description under 80 characters and use sentence case for it, even if the project's webpage or readme uses another capitalisation. Demo links should only be used for interactive demos, i.e. not video demonstrations. - [Outline](https://getoutline.org/) - A toolset to run shadowsocks service and a service management API easily, including client apps. ([Source Code](https://github.com/Jigsaw-Code/?q=outline)) `Apache-2.0` `TypeScript`
• [x] Submit one item per pull request. This eases reviewing and speeds up inclusion.
• [x] Additions are inserted preserving alphabetical order.
• [x] Additions are not already listed at awesome-selfhosted
• [x] The Language tag is the main server-side requirement for the software. Don't include frameworks or specific dialects.
• [x] You have searched the repository for any relevant issues or PRs, including closed ones.
• [x] Any category you are creating has the minimum requirement of 3 items.
• [x] Any software project you are adding to the list is actively maintained.
• [x] The pull request title is informative, unlike "Update README.md". Suggested titles: "Add aaa to bbb" for adding software aaa to section bbb, "Remove aaa from bbb" for removing, "Fix license for aaa", etc.

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Please take some time to answer the following questions as best you can:

• Why is it awesome?

It is easy to use with very intuitive and easy to manage applications.

• Have you used it? For how long?

Yes, I had for few months.

• Is this in a personal or professional setup?

It could be both.

• How many devices/users/services/... do you manage with it?

N/A

• Biggest pros/cons compared to other solutions?

Easy to use for admins and also for users as it has dedicated management app and clients for each platform.

[nodiscc]

Sorry, the answers to the questions in the PR template are insufficient.