Deprecate helm2, use helm3lib by default

[diafour]

Is your feature request related to a problem? Please describe.

Helm 2 is deprecated a year ago (https://helm.sh/blog/helm-v2-deprecation-timeline/). Recently helm3lib is implemented.

Describe the solution you'd like to see

1. I think we can drop helm2 support and hacks from the codebase and helm3 binary from the image to reduce its size for the next minor release (1.1.0).

2. We can provide an example of using helm2to3 as a module to migrate from addon-operator 1.0.x to 1.1.x.

3. We can provide an example of disabling helm3lib by ADD-ing helm3 binary into the custom image.

4. Graceful exit if helm2 modules are detected.

Describe alternatives you've considered

No alternatives. addon-operator image is oversized: there is helm3 as binary and helm3 as a library inside the addon-operator binary.

Additional context