[radar-rest-sources-authorizer] Use default authUrl

[pvannierop]

Problem

By default, the rest-sources-authorizer would use localhost/managementportal/auth as authorization URL.

Solution

The application will use https://serverName/managementportal/oauth as default authUrl. A custom authUrl can be provided via the values.md file.

[github-actions]

Great PR! Please pay attention to the following items before merging:

Files matching charts/*/values.yaml:

• Is the PR adding a new container? Please reviewer, add it to the models (internal process)
• Is the PR adding a new parameter? Please, ensure it’s documented in the README.md

This is an automatically generated QA checklist based on modified files.

[keyvaann]

LGTM