Reload now works without filling in device credentials
Implement device configuration UI and include "Edit Devices" button
Add support for timezones

- datetime objects should be stored internally using UTC format
- timezone selected by user then used to convert to UTC for report generation
- middleware remembers choice for current session
Add riverbed favicon
Refactor Shark view selection from devices.py to table options
Set some fields to read-only in device configuration form
Add uniform title tag to pages