[WIP] kind/documentation: Updating Readme according to the issue #33

[PatrickLaabs]

What this PR does / why we need it:

• Updates the README.md.
• Fixes broken links to the samples directory - which has been moved to 'templates'.
• Fixes the 'clusterctl generate' command for the Manifest creation, since the URL does not match with the current state
• Env-Vars updated
• Updates the displayed Version of the CAPI Controllers of the Harvester Provider at the bootstrapping phase.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged): Fixes #33

Special notes for your reviewer: None

Checklist:

• [x] squashed commits into logical changes
• [x] includes documentation
• [-] adds unit tests
• [-] adds or updates e2e tests