Add boat preferences CRUD

[schrockwell]

On /boats, we should be able to click a boat and modify some preferences for it, such as:

• Name
• Serial number
• Primary GPS data source
• Toggle sensor channel visibility
• Toggle sensor channel acceptability (i.e. do we persist incoming samples from this sensor?)

See this very sophisticated mockup:

Name:       [_______]
Serial:     [_______]
GPS source: [_______ v]

Sensor         Type                Visible?      Record data?
-----------------------------------------------------------
ABC-123        :magnetic_heading   [x] visible   [x] record data
FOOBAR         :water_depth        [x] visible   [x] record data
...