Added CMI-Extension

[YannicHock]

Your checklist for this pull request

🚨 Please review the guidelines for contributing to this repository.

• [ x] Make sure your name is added to Contributors file /Plan/common/src/main/java/com/djrapitops/plan/delivery/rendering/html/Contributors.java
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Description

Most of the work I did was for the extension itself and not this repo, that is why most of the explenation can be found here

Thank you!