feat(argo-cd): Add `existingVolumes` setting for remaining deployments with emptyDir volumes

[bodgit]

#2410 added the existingVolumes setting for the repo-server component. This PR adds an equivalent setting to the other Argo CD components that have emptyDir volumes in their deployment so you can either use a PVC or further tune the emptyDir volume with sizeLimit parameters, etc. (which is what I do).

Checklist:

• [x] I have bumped the chart version according to versioning
• [x] I have updated the documentation according to documentation
• [x] I have updated the chart changelog with all the changes that come with this pull request according to changelog.
• [x] Any new values are backwards compatible and/or have sensible default.
• [x] I have signed off all my commits as required by DCO.
• [x] My build is green (troubleshooting builds).

[yu-croco]

FYI Regarding the failed CI, https://github.com/argoproj/argo-helm/issues/2460 is related. There is a PR for fixing in upstream, let's wait for it.

[yu-croco]

FYI: The CI is fixed now. 👍

[bodgit]

@yu-croco Rebased and all tests now pass.

[github-actions[bot]]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[mbevc1]

Probably needs rebasing rather than closing? :thinking:

[yu-croco]

Hi @bodgit , can you please fetch latest remote diff and resolve conflicts?