Allow for custom role/meta definition

### Description

Requested here: https://app-eu1.hubspot.com/help-desk/26586079/view/233410279/ticket/81753305284/thread/10024322274#email

### Description

- Ability to define meta data (exact request was custom "roles") on Members within a FlowFuse team, such that business and auth logic within a Dashboard application can utilise FlowFuse's central user management

### Related Issues

https://github.com/FlowFuse/node-red-dashboard-2-user-addon/issues/21

### Customers Requesting

- https://app-eu1.hubspot.com/contacts/26586079/record/0-2/10177258183

### Which customers would this be available to

Team + Enterprise Tiers (EE)

### Have you provided an initial effort estimate for this issue?

I have provided an initial effort estimate