docs: 2.0.0 updates

[polarweasel]

How would you describe the priority of this documentation request

High

Please provide a link or source to the relevant docs

https://docs.nvidia.com/infra-controller

Describe the problems in the documentation

Final updates for the 2.0.0 docs release:

• remove versioning
• add "New" badge to selected features
• badge any deprecated items
• cut over to new release note (Fern changelog) format

(Optional) Propose a correction

No response

Code of Conduct

• I agree to follow NVIDIA Infra Controller's Code of Conduct
• I have searched the open documentation issues and have found no duplicates for this documentation issue

[AlexGridnev]

I've removed milestone for reporting purposes to keep things clean. Technically this should be done after the Go signal IIUC

[polarweasel]

Docs are live with PR #4456