Improve linux documentation and application information available to the user

[odockal]

In the extension, and in the README in the repo, we should be more transparent about linux configuration.

We have pd-docs: https://podman-desktop.io/docs/openshift/openshift-local.

But for someone simply using extension without further knowledge via PD, this is not anywhere visible.

I suggest to:

1. update README.md to contain link to a docs and simple mac/win/linux installation process from crc-extension point of view, aka:

On linux, read www.xy.link, for now, you have to download crc manually and run crc-setup via cli (explaining preset configuration). 

2. Do not allow user to run some unsupported functionality (update should not be possible, same as running Initialize and Start, start only should be allowed)
3. Improve links in the OpenShift local dashboard so we point to correct docs, we point to crc mostly, but it should be podman-desktop.io: