chore: rename the tutor-multi references to harmony

[MoisesGSalas]

Description

This changes all the previous references to the tutor-multi placeholder name to harmony. I opted to use only "harmony" in everything related to the chart and "k8s_harmony" for the references in the tutor plugin code.

closes #18

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[bradenmacdonald]

I tested this today and confirmed that the helm chart installs into the cluster, and the plugin installs into the Tutor environment. Thanks @MoisesGSalas, great work!

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