Gitlab CI/CD dependencies license check

[ivakoleva]

Add Licenses whitelist & validation on PR Gitlab check.

• SDK uses https://github.com/raimon49/pip-licenses, that supports allow-only verifying licenses match a list of permitted ones.
• Control Service uses https://github.com/jk1/Gradle-License-Report plugin, that supports licenses file (whitelisting) to be verified by task checkLicense.

Find Dependencies licensing page on generating dependencies license report (, then cleanup sections after enabling license verification?). Add a sentence about license check in CONTRIBUTING.md.