Refactor metadata route to properly add generation status within the route

[HerveRI]

Fixes #2081. Refactor metadata route to properly add generation status within the route.

[anth-volk]

Hey Hervé! Could you do the following:

1. Name this PR something describing what you're doing
2. Add "Fixes #ISSUE_NUMBER" (fill in the number, no quotes) as the first line in the PR description

I'll review the technical content either later today or Monday

[anth-volk]

Hi @HerveRI, thanks for your contributions! I've left a few comments here, but looking forward to hopefully having this reviewed and merged by the end of this week.

[anth-volk]

Suggested change

	- "metadata_route to add status and message values to the
	- metadata_route to add status and message values to the response object

nitpick, nonblocking: Remove quotes and ensure items are on one line

While YAML does allow for items to be spread across lines, we don't typically do so, and tend to add lines without quotes

[anth-volk]

issue, blocking: Remove the result key and refactor

Your work here removing status and message and placing them within the route handler is exactly what we're looking for. However, the code here and below (I'll leave a separate comment illustrating it) creates a doubly-nested result key, breaking the metadata code. To fix this, I'd recommend removing the result key here and just returning the dictionary that is its value.

[anth-volk]

Thanks for these changes @HerveRI! These all look good. Approving.