[VPA] Add support for setting a custom request-to-limit ratio at the VPA object level

[iamzili]

Which component are you using?:

vertical-pod-autoscaler
/area vertical-pod-autoscaler

Is your feature request designed to solve a problem? If so describe the problem this feature should solve.:

This proposal introduces a new mechanism that allows VPA users to adjust the request-to-limit ratio (for CPU, memory, or both) directly in the VPA object for an existing workload. This removes the need to manually update resource requests and limits in workload API objects (such as Deployments) to set a new ratio and helps prevent unnecessary Pod restarts.

Describe the solution you'd like.:

AEP: #8516
Related Issue: #8401

[iamzili]

/assign

[omerap12]

/triage-accepted