This is a major refactor of the install/upgrade code which removes the config protobuf and replaces it with a config overrides secret which stores overrides to the values struct. Further background on this change can be found here: https://github.com/linkerd/linkerd2/discussions/4966
Note: as-is this PR breaks injection. There is work to move injection onto a Values-based config which must land before this can be merged.
A summary of the high level changes:
* the install, global, and proxy fields of linkerd-config ConfigMap are no longer populated
* the CLI install flow now follows these simple steps:
* load default Values from the chart
* update the Values based on the provided CLI flags
* render the chart with these values
* also render a Secret/linkerd-config-overrides which describes the values which have been changed from their defaults
* the CLI upgrade flow now follows these simple stesp:
* load the default Values from the chart
* if Secret/linkerd-config-overrides exists, apply the overrides onto the values
* otherwise load the legacy ConfigMap/linkerd-config and use it to updates the values
* further update the values based on the provided CLI flags
* render the chart and the Secret/linkerd-config-overrides as above
* Helm install and upgrade is unchanged
Signed-off-by: Alex Leong <alex@buoyant.io>