Each directory with tests should have a sig label in its OWNERS file to
document which SIG is responsible for the test. Otherwise SIG Testing gets
pinged by SIG Release as the default owner of all tests when a test fails.
Some integration test packages are either empty (objectmeta) or useless with
unclear owner (configmap); those get removed.
UserInfo contains a uid field alongside groups, username and extra.
This change makes it possible to pass a UID through as an impersonation header like you
can with Impersonate-Group, Impersonate-User and Impersonate-Extra.
This PR contains:
* Changes to impersonation.go to parse the Impersonate-Uid header and authorize uid impersonation
* Unit tests for allowed and disallowed impersonation cases
* An integration test that creates a CertificateSigningRequest using impersonation,
and ensures that the API server populates the correct impersonated spec.uid upon creation.
