Verify external content is accessible before performing sync

1. Feature Overview

There should be a way to check that an external source is available before trying to sync. 

Background, and strategic fit

An outage on console.redhat.com caused our Project sync to fail and all subsequent jobs to not run (silently). This is the error from the Project Sync when it tried to update the collections:

"ERROR! Error when finding available api versions from server (https://console.redhat.com/api/automation-hub/content/<id>-synclist/) (HTTP Code: 500, Message: Internal Server Error)"

As a result, the Project went into a failed state and all scheduled jobs for that Project failed until we manually re-ran the Project Sync.

Use Cases

A checkbox should be added on the Project template for "Verify External Content Exists" and a tooltip stating something like, "checking this box will perform a check to make sure external content is available before performing the sync"