Convert LinkML to ttl during poetry install and poetry run pytest

[dnlbauer]

This adds the functionality to automatically convert linkml definitions to shacl files during the install process.

There is a build script build.py that walks through the profiles and converts all linkml files it can find to shacl if the linkml version is newer than the shacl one. It can be triggered by running poetry install or by manually running build.py.
I also made sure it is running before any unit test to be sure they are executed against the newest defintions.