Add UI controls for VM Inject Partition and Disk Persistence

[jacdavi]

Makes the following changes:

• Adds column in StoppedExperiments for setting inject partition
• Adds column in StoppedExperiments for toggling persistence (snapshot) on and off
• Fixes issue with disk dropdowns not populating (Disk dropdown not populating in UI #161)
• Removes date in known_policy.go generation so file isn't updated every build
• Minor tweaks to column with in StoppedExperiments table

Note: I did not directly write all of these changes, but have pulled them up from an internal repo

[activeshadow]

Thanks @jacdavi I'll take a look at this ASAP!