Add domain toggle for websites

Working in enterprise ICT in a place running Windows means we have multiple accounts with tiered access. 
Some account credentials are used in multiple places with some things expecting the username with and some without the domain. 
I.e. thing A will expect the username format of `username` and thing B will expect `domain\username`

This would mean you need two 1Password entries to have working autofill. 

If there was an option in the settings to add a (or multiple) domains and then in each credential there was a toggle (or dropdown) next to each website to specify if it should also get `domain\` (or just a specified prefix) before the username. 

So in this exquisite drawing signing in to #1 would use `username` and #2 would use `domain\username`