A few miscellaneous tweaks

[bennybp]

Description

A few random miscellaneous cleanups/fixes

• Fix docs: There is no longer a default for the server
• Handle case where there is no user-agent string
  • Typically a bot, but at least the server shouldn't raise an exception
• Move the flask blueprints and related functions to the flask_app directory

Changelog description

N/A

Status

• Code base linted
• Ready to go

[codecov]

Codecov Report

Merging #757 (54099e2) into main (e9f85cc) will increase coverage by 0.01%.
The diff coverage is 71.97%.

Additional details and impacted files