Replace model related instances of tenant

This CR renames the instances of the word tenant for projects in the
cases where there is a relation to the models. In addition, the proper
migration scripts where writen.

Partially implements: blueprint replace-concept-of-tenants-for-projects

Change-Id: Ifcd773b31f65704737f2925ee67743df39ec50f7
Merge "Replace model related instances of tenant"