ZEVA2 - upgrade to prisma 7 and transition to migrations

**Describe the task**
Upgrade to prisma 7 and transition to migrations

**Purpose**
Necessary before we go to production.

**Acceptance Criteria**
- [ ] Prisma upgraded to v7.
- [ ] Migrations folder created, with an initial (baseline) migration.
- [ ] Create a new `migrate` script in package.json, and use this script in the openshift Dockerfile in place of `pushAndSeed`; also, should use this script as part of the `dev` script (in place of `pushSchemaToDB`).

**Additional context**
See the upgrade to v7 guide here: https://www.prisma.io/docs/orm/more/upgrade-guides/upgrading-versions/upgrading-to-prisma-7, and the transition to migrations guide here: https://www.prisma.io/docs/orm/prisma-migrate/getting-started#adding-prisma-migrate-to-an-existing-project.