Merge bugzilla.py module with models.py (mozilla#183)

* Delete `bugzilla` module, move all models to `models.py`
Since `bugzilla.py` was a collection of Pydantic BaseModels, in this commit we
move them into `models.py` so that it is the one source of all models used in the
app.
When making this move, I noticed that there were some methods on
`WebhookComment` model that were unused, so I deleted them.

Author: grahamalama

jbi/actions/default.py

@@ -7,9 +7,9 @@
 import logging
 
 from jbi import ActionResult, Operation
-from jbi.bugzilla import BugzillaBug, BugzillaWebhookRequest
 from jbi.environment import get_settings
 from jbi.errors import ActionError
+from jbi.models import BugzillaBug, BugzillaWebhookRequest
 from jbi.services import get_bugzilla, get_jira
 
 settings = get_settings()

jbi/actions/default_with_assignee_and_status.py

@@ -14,7 +14,7 @@
     JIRA_REQUIRED_PERMISSIONS as DEFAULT_JIRA_REQUIRED_PERMISSIONS,
 )
 from jbi.actions.default import DefaultExecutor
-from jbi.bugzilla import BugzillaBug, BugzillaWebhookRequest
+from jbi.models import BugzillaBug, BugzillaWebhookRequest
 
 logger = logging.getLogger(__name__)