Feature Description

• One-line feature description (can be used as a release note): Introduces a lightweight monitoring component for serving the core resource metrics API used by the Horizontal Pod Autoscaler and other components.
• Primary contact (assignee): @piosz
• Responsible SIG: sig/instrumentation
• Design proposal link (community repo): Metrics server
• Reviewer(s) - (for LGTM) recommend having 2+ reviewers (at least one from code-area OWNERS file) agreed to review. Reviewers from multiple companies preferred: @DirectXMan12
• Approver (likely from SIG/area to which feature belongs): @DirectXMan12
• Initial target stage (alpha/beta/stable) and release (x.y): alpha in 1.7, beta in 1.8