add OmniTools

[Rabenherz112]

This PR is part of a series aimed at including interesting projects I've discovered over the past year. I'm working through my list and suggesting additions for anything that meets the criteria. Feel free to prioritize other addition PRs over this one if needed.
_{Note: These are projects I found interesting but haven't personally tested or used extensively.}

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]):

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[kokomo123]

LGTM, no issues here pending further thoughts from collaborators