Major Helm refactor

[duhow]

Description of the change

I wanted to deploy Rudderstack in my Kubernetes cluster, but faced lots of issues.
So I spent the whole day tweaking the Helm Chart, cleaning up some stuff, fixing some settings...

Here's a list of changes (not all included):

• Remove subchart downloaded dependencies (old postgresql)
• Migrate transformer chart into rudderstack
• Add bitnami/postgresql Chart dependency
• Move to subfolder charts/rudderstack so in the future you can generate Helm Repository and publish into ArtifactHub or others.
• Migrate most of values ENV into Secret and ConfigMap, allow to customize by Helm values
• Replace livenessProbe by startupProbe
• Change wait-for commands by initContainer
• Update config enableStats matching telegraf status (stop spamming cannot connect to statsd)
• Rename values keys to standard Chart names (eg. version -> tag)
• Update appVersion to match latest fix version 1.43.1
• Bump Chart version from 0.7.0 to 0.8.0

Type of change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklists

Development

• Lint rules pass locally
• The code changed/added as part of this pull request has been covered with tests
• All tests related to the changed code pass in development

Code review

• This pull request has a descriptive title and information useful to a reviewer. There may be a screenshot or screencast attached
• "Ready for review" label attached to the PR and reviewers mentioned in a comment
• Changes have been reviewed by at least one other engineer
• Issue from task tracker has a link to this pull request

[contributor-support]

Thank you @duhow for contributing this PR.
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