Read xml metadata from a url when setting the config

[deepakprabhakara]

Is your proposal related to a problem?

Read XML metadata from a URL if available.

Describe the solution you'd like

Currently, we require the raw XML metadata in the config request. We should support pulling this from a URL instead.

Additional context

There are security implications to reading data from an external URL since it becomes a source of an attack. We should safeguard the reading contents of the URL (limit the payload, aggressive timeouts, etc.).