support multiple corpus accounts (#334)

Add support for sharding across multiple storage accounts for blob containers used for corpus management.

Things to note:

1. Additional storage accounts must be in the same resource group, support the "blob" endpoint, and have the tag `storage_type` with the value `corpus`.  A utility is provided (`src/utils/add-corpus-storage-accounts`), which adds storage accounts. 
2. If any secondary storage accounts exist, they are used by default for containers.
3. Storage account names are cached in memory the Azure Function instance forever.   Upon adding new storage accounts, the app needs to be restarted to pick up the new accounts.

src/api-service/__app__/onefuzzlib/notifications/ado.py

@@ -25,6 +25,7 @@ from azure.devops.v6_0.work_item_tracking.work_item_tracking_client import (
 )
 from memoization import cached
 from onefuzztypes.models import ADOTemplate, Report
+from onefuzztypes.primitives import Container
 
 from .common import Render, fail_task
 
@@ -49,7 +50,7 @@ def get_valid_fields(
 
 class ADO:
     def __init__(
-        self, container: str, filename: str, config: ADOTemplate, report: Report
+        self, container: Container, filename: str, config: ADOTemplate, report: Report
     ):
         self.config = config
         self.renderer = Render(container, filename, report)
@@ -200,7 +201,7 @@ class ADO:
 
 
 def notify_ado(
-    config: ADOTemplate, container: str, filename: str, report: Report
+    config: ADOTemplate, container: Container, filename: str, report: Report
 ) -> None:
     logging.info(
         "notify ado: job_id:%s task_id:%s container:%s filename:%s",

src/api-service/__app__/onefuzzlib/notifications/common.py

@@ -9,6 +9,7 @@ from typing import Optional
 from jinja2.sandbox import SandboxedEnvironment
 from onefuzztypes.enums import ErrorCode
 from onefuzztypes.models import Error, Report
+from onefuzztypes.primitives import Container
 
 from ..azure.containers import auth_download_url
 from ..azure.creds import get_instance_url
@@ -33,7 +34,7 @@ def fail_task(report: Report, error: Exception) -> None:
 
 
 class Render:
-    def __init__(self, container: str, filename: str, report: Report):
+    def __init__(self, container: Container, filename: str, report: Report):
         self.report = report
         self.container = container
         self.filename = filename

src/api-service/__app__/onefuzzlib/notifications/github_issues.py

@@ -11,13 +11,18 @@ from github3.exceptions import GitHubException
 from github3.issues import Issue
 from onefuzztypes.enums import GithubIssueSearchMatch
 from onefuzztypes.models import GithubIssueTemplate, Report
+from onefuzztypes.primitives import Container
 
 from .common import Render, fail_task
 
 
 class GithubIssue:
     def __init__(
-        self, config: GithubIssueTemplate, container: str, filename: str, report: Report
+        self,
+        config: GithubIssueTemplate,
+        container: Container,
+        filename: str,
+        report: Report,
     ):
         self.config = config
         self.report = report
@@ -95,7 +100,10 @@ class GithubIssue:
 
 
 def github_issue(
-    config: GithubIssueTemplate, container: str, filename: str, report: Optional[Report]
+    config: GithubIssueTemplate,
+    container: Container,
+    filename: str,
+    report: Optional[Report],
 ) -> None:
     if report is None:
         return

src/api-service/__app__/onefuzzlib/notifications/main.py

@@ -21,12 +21,12 @@ from onefuzztypes.models import (
 from onefuzztypes.primitives import Container, Event
 
 from ..azure.containers import (
-    StorageType,
     container_exists,
     get_container_metadata,
     get_file_sas_url,
 )
 from ..azure.queue import send_message
+from ..azure.storage import StorageType
 from ..dashboard import add_event
 from ..orm import ORMMixin
 from ..reports import get_report

src/api-service/__app__/onefuzzlib/notifications/teams.py

@@ -8,6 +8,7 @@ from typing import Any, Dict, List, Optional
 
 import requests
 from onefuzztypes.models import Report, TeamsTemplate
+from onefuzztypes.primitives import Container
 
 from ..azure.containers import auth_download_url
 from ..tasks.config import get_setup_container
@@ -51,7 +52,7 @@ def send_teams_webhook(
 
 
 def notify_teams(
-    config: TeamsTemplate, container: str, filename: str, report: Optional[Report]
+    config: TeamsTemplate, container: Container, filename: str, report: Optional[Report]
 ) -> None:
     text = None
     facts: List[Dict[str, str]] = []