Check URL connectivity, check for incorrect image names
feat: Error out if using appSRE source and not on internal network (#…
…257)
* feat: Error out if using appSRE source and not on internal network
Add a check_connection function to error out if we can't reach required
sources when running bonfire. Without this we hang for a very long time.
This also adds a message to inform the user to check their VPN
connection.
Signed-off-by: Stephen Adams <stephen.adams@redhat.com>
Co-authored-by: Brandon Squizzato <bsquizza@redhat.com>