Add support for passing charmcraft.yaml as metadata to testing.Context

[tonyandrewmeyer]

Description

Charmcraft.yaml (replacing metadata.yaml) now removes the need to have different files for metadata, config, and actions. When providing metadata in the charmcraft.yaml format, we get a InconsistentScenarioError error because the config option is not recognized.

METADATA = yaml.safe_load(Path("tests/unit/charms/tls_certificates_interface/v4/dummy_requirer_charm/charmcraft.yaml").read_text())
state_in = scenario.State(
    config={"common_name": "example.com"},
)
ctx = scenario.Context(
    charm_type=DummyTLSCertificatesRequirerCharm,
    meta=METADATA,
)

Logs

scenario.runtime.InconsistentScenarioError: Inconsistent scenario. The following errors were found: config option 'common_name' in state.config but not specified in config.yaml.

Desired state

self.ctx = scenario.Context(
    charm_type=DummyTLSCertificatesRequirerCharm,
    meta=METADATA,
)

Workaround

self.ctx = scenario.Context(
    charm_type=DummyTLSCertificatesRequirerCharm,
    meta=METADATA,
    config=METADATA["config"],
    actions=METADATA["actions"],
)

Moved from canonical/ops-scenario#156