[cms] Peer review line items based on their domain, not account domain

[xaur]

This issue is to change the current same-domain review visibility from the current rule

Users can see invoices of other users in the same domain

to

Users can see line items of the same domain as their account

Currently, if my domain is Marketing and another user with domain=Development submits a line item with domain=Marketing, I cannot review that line item, because I cannot see that invoice, because its submitter is in the different domain.

I suggest to change this visibility rule to compare my domain with line item domain regardless of what domain its submitter belongs to.

This change has some implications for the current system:

• I will start seeing invoices that were not shown previously because their submitters are in different domains. I call these "surrogate" invoices because they are only necessary to have some container to place matching items.
• I should stop seeing line items of domains other than mine.

[xaur]

Tested, currently bugged by #1424 but otherwise works as expected. Thanks!