User needs to specify `id` for organisations and vaults

[IanMayo]

I hadn't realised, but in the legacy data abbreviated versions of the name of the organisation/vault are present in the id field.

So, when creating these two resources users need to be able to specify the value to be used as id.

In the edit form they should be editable, but should carry the same "edit carefully" warning we show for the catCode etc tables.

Update: I'm consciously deferring this for a future development cycle, since it is unlikely that new orgs or vaults will be added anytime soon.