This script has slightly diverged between development and 3.6. This task is to:

• reconcile the two branches;
• move the script to the framework;
• adapt the path everywhere the script is invoked.

Note: this task is only about mbedtls and the framework. If changes are needed to adapt to tf-psa-crypto, another task should be created about that (unless the resulting task would be XS, in which case let's do it as part of this task).