ecctl commands to manage CA Certificates in ECE Platform

## Overview
An interesting use case from Georgia Tech -
They had issues with their certificate chain but couldn't remediate those since the UI was not functional during those issues.

They asked for ecctl to be able to upload CA Certificates alongside the UI functionality that exists to manage that.
They ended up calling support and using "curl" to fix this, outside the UI.

## Suggested UX
`ecctl platform certificate show` -> would show the current cert chain in the terminal
`ecctl platform certificate upload --file ` -> would upload the specified cert to ECE from the local filesystem.