Can define secrets and expose them as env vars in dynamic services

[pcrespov]

Following up from comments in ITISFoundation/osparc-simcore#3526

The user can define some secret variables in the Preferences tab. These variables are treated as secrets i.e. they will be encrypted in the database. When a dynamic service starts, they will be exposed as env vars

This is a mechanism that is frequently used in CI settings etc ... See as examples

• https://docs.github.com/en/actions/security-guides/encrypted-secrets
• https://docs.gitlab.com/charts/installation/secrets.html

[pcrespov]

Issue moved to ITISFoundation/osparc-issues #764 via Zenhub