Add regex option to redirects command

Add --redirect-site-regex option to the redirects command to allow name
patterns to be used in addition to the full site names passed via
--redirect-site. Set the default patterns so that some common feed proxy
URL schemes are covered.
fix up log configuration

Configure the requests library to not log outgoing connections unless
the app is run with high verbosity.

Remove some old log configuration code that was no longer being used.
Add sites command

Add a new command to produce a list of the unique sites referenced in
all bookmarks.