[FR] Add role/group mapping for oidc authentication

[Ch1mCh4]

Is your feature request related to a problem? Please describe.
Currently, DFIR-IRIS only maps the OIDC user information to USERNAME and EMAIL environment variables. However, there is no mechanism to automatically map user roles/groups from OIDC. This means that user group assignments must be manually configured after user creation, which is inefficient and requires additional administrative effort.

Describe the solution you'd like
Introduce a new environment variable OIDC_MAPPING_USERGROUP, which maps to a key provided by the OIDC authentication response that contains the user's group or role information.

• This variable should be used to determine the group membership of a user.
• If a new user is created, they should automatically be assigned to the appropriate group based on this value.
• If an existing user logs in and their role has changed, the group assignment should be updated accordingly.

This would streamline user management by ensuring that role-based access control is dynamically handled via OIDC.

Describe alternatives you've considered

Manually assigning users to groups after creation, which is time-consuming and error-prone.

Additional context

we work with iris in a kubernetes cluster which provides an oidc provider via keycloak through which users can authenticate themselves to various applications (including iris). The users can be assigned a role such as administrator or analyst in keycloak which is then taken over by the applications.