Retrieve 'my' workspaces

[christoferlof]

Description

As a researcher
I want to see the list of workspaces that I have access to
So that I more easily can find them rather than seeing all workspaces within the organization

Acceptance criteria

• GET /workspaces only returns workspaces that the current user is assigned researcher or workspace owner role to
• GET /workspaces returns all workspaces for users that have the role TRE Administrator

Note on implementation

We'll rely on the identity provider's capability to list applications a user has access to. For Azure AD we should query the Graph to get appRoleAssignments for the current user, and then filter/join by resourceId to match with oidcApplicationId on each workspace.
This will likely require us to create an abstraction or client for different Idp's. Atm we'll only implement Azure AD.

Depends on #307 to be finished