Fix test failure caused by making genconfig trackerless When I removed the need to have a tracker for genconfig, I broke a couple of tests. The breakage was hidden by a bad workflow. This change allows the tests to pass and refactors reporting of UsageError exceptions in admin.py. It also adds a test for failure in install command as there is a test case for it and this test tests the refactor.

# human timezones
pytz
# indexer
Whoosh
# xapian is also installed
# extra database support
psycopg2
mysqlclient
redis
# encryption
gpg
# java web tokens
PyJWT
# extra HTTP compression methods
Brotli
zstd
# jinja2 template engine
Jinja2