feat: add leafwiki

[perber]

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

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

• Submit one item per pull request. This eases reviewing and speeds up inclusion.
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[kokomo123]

LGTM, no issues here pending further thoughts from collaborators as I have throughly looked through this repo. Thank you for your contribution!

[kokomo123]

As changes have been made, lgtm