Investigate combining portfolio invitations and user portfolio permissions

[allly-b]

Issue description

We have discussed combining domain invitations and user domain roles (in #3552 ); however our architecture for portfolio invites and user portfolio permissions was based on the domain invitation/userdomain role architecture. Based on the results of #3552 we should make the same or similar changes to user portfolio permissions and portfolio invitations.

Current issues with portfolio invitations:

• increased complexity on displaying Org members Table as we need to check both models
• increased complexity on displaying org model Member Profile page (needs to change based on the object in question.
• increased complexity when updating portfolio permissions for a user

Acceptance criteria

• create plan of action for reducing complexity ( or close ticket if deemed not feasible)
• get lead and engineering feedback on the plan
• Implement the plan

Additional context

• please create plan items as sub issues of this ticket.
• email sending should be considered as part of this

Links to other issues

• blocked by Domain invitation/ userdomain role consolidate logic #3552