bug: fix traceback in roundup-admin init with bad config values initialize accepts setting values for config.ini file settings. If they are not valid, you got a python traceback. ConfigurationError exceptions are now trapped. The admin.py's usageError_feedback method is used to inform the user. Also the feedback message now starts with a newline making it easier to read by separating it from command that caused the issue.

# https://issues.roundup-tracker.org/issue2551278
# datetime.utcnow deprecated
try:
    from datetime import UTC, datetime

    def utcnow():
        return datetime.now(UTC)

except ImportError:
    from datetime import datetime

    def utcnow():
        return datetime.utcnow()