MigrScripts: delete perms linked to excluded roles

The migration script createSQLDataMigration.groovy excludes some Roles
from migration (in particular, SYSTEM ADMINISTRATORS).

Fix: delete from the Permissions table all entries pointing to the
excluded roles.
Scripts: use wildcardPerm in both setup and upgr.

Modify both versions of createFRBaseEnvironment.groovy (both in setup
and upgrade/major-rleases/2) to use wildcardPermission
(Permission.defaultPerm) instead of adminPerm (which points to
AllPermission).

The notation Permission.defaultPerm is consistent with the rest of the
code base (and is synonymous with Permission.wildcardPerm).
MigrScripts: createFRBaseEnvironment: check-exists

Make scripts/upgrades/major-release/2/createFRBaseEnvironment.groovy
check if the Roles, Permissions and Subjects already exist before
creating them.

That makes this script restartable - and also works around situation
when a role introduced it FR2 (like federation-reporting) had been
manually created in an FR 1.x instance.
Merge pull request #151 from University-of-Auckland/aaf-develop

Migration scripts: fix permissions handling, permission types and check for existing roles