Adjust Rest-Template to add Token by default

[lmoesle]

We have to provide a token (token of the service account digiwf) in REST requests to the S3 service. The S3 authorizes digiwf with the provided token.

Todo

• In the S3 client we have to add a token (token of the service account digiwf) to Http requests
• The token S3 client reads the token from an Env variable
• The S3 service (backend) authorizes digiwf based on the token
• The S3 service keeps track of authorized applications
• Token is send via HTTP Header or Basic auth
• Change to WebClient

Extra Ticket

• S3 service verifies token based on a config map Criteria
• S3 service authorizes application based on the provided token

Criteria

• Token is provided in Http requests to the S3 service
• Token is saved as Env variable

[dominikhorn93]

• Check if this is done with Keycloak ServiceAccounts
• Configure a role for S3 Services
• A service account should get a specific role for the client of the s3 service
• digiWF-engine keycloak client should get the "user" role for the P10 keycloak client