Remove Codenotary integrity check (#6236)

* Formally deprecate CodeNotary build config

* Remove CodeNotary specific integrity checking

The current code is specific to how CodeNotary was doing integrity
checking. A future integrity checking mechanism likely will work
differently (e.g. through EROFS based containers). Remove the current
code to make way for a future implementation.

* Drop CodeNotary integrity fixups

* Drop unused tests

* Fix pytest

* Fix pytest

* Remove CodeNotary related exceptions and handling

Remove CodeNotary related exceptions and handling from the Docker
interface.

* Drop unnecessary comment

* Remove Codenotary specific IssueType/SuggestionType

* Drop Codenotary specific environment and secret reference

* Remove unused constants

* Introduce APIGone exception for removed APIs

Introduce a new exception class APIGone to indicate that certain API
features have been removed and are no longer available. Update the
security integrity check endpoint to raise this new exception instead
of a generic APIError, providing clearer communication to clients that
the feature has been intentionally removed.

* Drop content trust

A cosign based signature verification will likely be named differently
to avoid confusion with existing implementations. For now, remove the
content trust option entirely.

* Drop code sign test

* Remove source_mods/content_trust evaluations

* Remove content_trust reference in bootstrap.py

* Fix security tests

* Drop unused tests

* Drop codenotary from schema

Since we have "remove extra" in voluptuous, we can remove the
codenotary field from the addon schema.

* Remove content_trust from tests

* Remove content_trust unsupported reason

* Remove unnecessary comment

* Remove unrelated pytest

* Remove unrelated fixtures

tests/docker/test_interface.py

@@ -31,15 +31,6 @@ from supervisor.jobs import JobSchedulerOptions, SupervisorJob
 from tests.common import load_json_fixture
 
 
-@pytest.fixture(autouse=True)
-def mock_verify_content(coresys: CoreSys):
-    """Mock verify_content utility during tests."""
-    with patch.object(
-        coresys.security, "verify_content", return_value=None
-    ) as verify_content:
-        yield verify_content
-
-
 @pytest.mark.parametrize(
     "cpu_arch, platform",
     [