Add additional fields for data at underwater sites

[emjaymur]

We'd like to collect some additional information about underwater sites, including water conditions, environmental conditions, surrounding habitat, and additional threats. Can get better list from the underwater folks when we're ready to move on this.

[mradamcox]

Sounds like this can be appropriately handled by adding a new Step in the resource model, similar to the existing Step 5 that is only for structures. It's likely that this addition will not cause any of the issues seen in ticket #80.

[mradamcox]

putting this on hold at the moment as it's out of current scope