Remove references to global in individual charts

[faisal-memon]

A lot of individual component charts refer to global values. This was done when we had a single chart that deployed all components. In moving to multiple root level charts, the individual charts don't have a global section.

https://github.com/spiffe/helm-charts/pull/311 adds a global section to all the nested charts to workaround this issue. A proper fix is to not rely on globals in the nested charts.