This was recommended by Enes, and is more aligned with the model
naming (the model is Account).
This was a completely mechanical change, using the following code:
```
sed -i -e 's/current_user/current_account/' `git grep -l 'current_user' clover*.rb routes/clover_base.rb routes views`
```
This makes some naming more consistent, such as `account_ubid: current_account.ubid`.
This makes some naming less consistent, such as `user: current_account`
We could fix the less consistent naming by changing
`Routes::Common::Base#initialize` to use `account` instead of `user` as a
keyword argument. This commit doesn't make that change. It's likely
Routes::Common will go away when merging CloverWeb and CloverApi, so
I'm not sure it's worth it.