FN-2 - Keycloak and Flask initialization

[r-casula]

This is the first PR it will include:

• Initialization of a Keycloak service with a custom realm import, admin user initialization on the new realm, and token exchange service
• Initialization of the Flask backend service which provide full list of endpoints (except for token transfers, and task pod execution)
• Helm chart templates for full deployment (tested on a local minikube instance)
• Basic code quality tools scripts that will be used in the CI/CD process (hadolint, pylint, and pipenv check for vulnerabilities in python deps)
• Unittest with coverage of 93%

This PR might get more updates as we go, I'll try to keep the commits to a minimum so those can be reviewed individually

[r-casula]

Will merge this pull request. If something does not align with FAIR integration it can be addressed on a dedicated PR