Figure out a Rego V1 migration plan

[evankanderson]

Open Policy Agent has released a v1.0.0. This includes making a number of features which were previously available under the import rego.v1 or other feature flags. (Yay!) The rego.v1 flag also removes or deprecates a number of syntax items to clean up the overall ecosystem.

Unfortunately, a number of the existing rules in https://github.com/mindersec/minder-rules-and-profiles are written using the "rego.v0" syntax, and fail to compile under the v1 rules. We need to figure out a plan for migrating existing usage from v0 to v1, probably with cooperation from users (in terms of adding a new field for rego syntax version or "regov1" evaluator), along with controls on which versions of Rego are accepted by existing projects.

☝️ The above is not a plan, we need to actually document a plan, including migration instructions.

[evankanderson]

Related: #5251 (the upgrade to OPA v1.0.0)