Clean up unused values for eFormidling after upgrade to integration point v4

### Description

After upgrading to version 4 of the integration point (integrasjonspunkt), several configuration values are now duplicated and some are no longer used.

### Additional Information

Identified duplicates:

SPRING_DATASOURCE_URL vs difi_datasource_url (both point to the same database)
SPRING_ACTIVEMQ_BROKERURL vs difi_activemq_broker-url (both point to the same ActiveMQ)
SPRING_DATASOURCE_USERNAME vs difi_datasource_username (both have the same value)

Outdated:
difi_move_dpo_username
difi_move_dpo_password

### Tasks
- [x] Verify which properties are used by integration point v4
- [ ] Remove deprecated/unused variables from helm chart values
- [ ] Remove deprecated/unused variables from pipelines
- [ ] Update documentation if relevant
- [ ] Test in test environment before production

### Acceptance criteria
Only necessary variables are defined in pipelines
No duplicate configurations exist
Deployments work as expected in all environments
Configuration follows integration point v4 conventions