Add user management

[maximiliani]

Is your feature request related to a problem? Please describe.
Right now, everybody can edit anything under anyones name. This should be significantly improved for v1.

Describe the solution you'd like

• Use Spring Security to limit access to modifying/deleting information
• Manage ACLs
• Use OAuth/OIDC (based on Keycloak) to fill user details and allow users to connect their ORCiD
• Handle deprovisioning of users
• Manage API Keys