- The certs manager controller, along with its sibling certs expirer
and certs observer controllers, are generally useful for any process
that wants to create its own CA and TLS certs, but only if the
updating of the APIService is not included in those controllers
- So that functionality for updating APIServices is moved to a new
controller which watches the same Secret which is used by those
other controllers
- Also parameterize `NewCertsManagerController` with the service name
and the CA common name to make the controller more reusable
- Add a unit test for each cert controller
- Make DynamicTLSServingCertProvider an interface and use a mutex
internally
- Create a shared ToPEM function instead of having two very similar
functions
- Move the ObservableWithInformerOption test helper to testutils
- Rename some variables and imports
- Refactors the existing cert generation code into controllers
which read and write a Secret containing the certs
- Does not add any new functionality yet, e.g. no new handling
for cert expiration, and no leader election to allow for
multiple servers running simultaneously
- This commit also doesn't add new tests for the cert generation
code, but it should be more unit testable now as controllers
