As a user I can see a retention policy management page

[nhaugo]

• Add a menu item for Database and Retention Policies
• Show existing DBs
• Show existing RPs for each DB
• Create database button
• Create, delete and edit for retention policies on each DB
• Allow user to edit RF, duration and default status for RPs
• Test behavior for changing default status or deleting current default of RPs
• Warn people on deletion of default RP