Merge pull request #1901 from dbcli/RW/migrate-cli-args-back-to-main-py

Migrate CLI argument handling back to `main.py`

Author: rolandwalker

changelog.md

@@ -4,6 +4,7 @@ Upcoming (TBD)
 Internal
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 * Factor `main.py` into several files using mixins.
+* Move CLI argument handling back to `main.py`.
 * Update Python versions used in CI.
 * Add CI on macOS.
 * Add limited CI on Windows.