Error early with ndjson inputs and support private wikis

If labswiki or labtestwiki is provided in the ndjson input the rerender will work up until that point and then fail. Similarly if a private wiki is provided we will receive errors from the api instead of the namespace map.

Fix with:

• Source the nsmap for all wikis up front, instead of one at a time as events are produced.
• Recognize the 'error' key from mwapi and throw an appropriate exception
• On error exit with an appropriate error code.
• Add a cli arg for providing an authorization header to pass on to mediawiki.
• Send events for private wikis to the private streams. This isn't concretely required, nothing will fail, but it can be confusing to see private events in the public version of the stream.