feat: enable key rotation (#15066)

This PR contains the remaining logic necessary to hook up key rotation
to the product.

coderd/cryptokeys/cache_test.go

@@ -488,7 +488,7 @@ type fakeFetcher struct {
 	called int
 }
 
-func (f *fakeFetcher) Fetch(_ context.Context) ([]codersdk.CryptoKey, error) {
+func (f *fakeFetcher) Fetch(_ context.Context, _ codersdk.CryptoKeyFeature) ([]codersdk.CryptoKey, error) {
 	f.called++
 	return f.keys, nil
 }