Split chart version from app version

[DrFaust92]

before i open a PR i wanted to get some feedback. Chart has its own lifecycle and we add features like https://github.com/apache/incubator-devlake-helm-chart/pull/344 (thanks for the quick review @klesh !)

and wed like to also see faster chart release cycles.

thoughts? if agreed i can open a PR to make this change

[klesh]

Loop @JorgeGar @matrixji

[matrixji]

For my understanding, we shoud split those 2 versions.