fix: add cue definitions for embedded types (#134)

This change refactors some embedded types within existing
definitions into definitions themselves.

This provides a pathway to much better go types being generated
by `make cuegen` and solving some of the pain observed in
https://github.com/revanite-io/pvtr-github-repo/blob/main/evaluation_plans/reusable_steps/evaluations_test.go#L21

Signed-off-by: Travis Truman <trumant@gmail.com>

chore: Updated this repo's SI: last reviewed date (#103)

Signed-off-by: Eddie Knight <knight@linux.com>

Rename schema to security-insights-schema.yaml (#65)

Signed-off-by: Eddie Knight <knight@linux.com>