Use Celery instead of RQ.

Celery provides a more robust set of queueing options for both tasks and
worker processes. Updates include:
- infrastructure necessary to run Celery, including celery entrypoint
- backgrounded functions are now imported directly from atst.jobs
- update tests as-needed
- update kubernetes worker pod command

atst/routes/applications/team.py

@@ -14,7 +14,7 @@ from atst.forms.team import TeamForm
 from atst.models import Permissions
 from atst.utils.flash import formatted_flash as flash
 from atst.utils.localization import translate
-from atst.queue import queue
+from atst.jobs import send_mail
 
 
 def get_form_permission_value(member, edit_perm_set):
@@ -129,7 +129,7 @@ def send_application_invitation(invitee_email, inviter_name, token):
     body = render_template(
         "emails/application/invitation.txt", owner=inviter_name, token=token
     )
-    queue.send_mail(
+    send_mail.delay(
         [invitee_email],
         translate("email.application_invite", {"inviter_name": inviter_name}),
         body,

atst/routes/dev.py

@@ -15,7 +15,7 @@ from atst.domain.exceptions import AlreadyExistsError, NotFoundError
 from atst.domain.users import Users
 from atst.domain.permission_sets import PermissionSets
 from atst.forms.data import SERVICE_BRANCHES
-from atst.queue import queue
+from atst.jobs import send_mail
 from atst.utils import pick
 
 
@@ -174,7 +174,7 @@ def dev_new_user():
 
 @bp.route("/test-email")
 def test_email():
-    queue.send_mail(
+    send_mail.delay(
         [request.args.get("to")], request.args.get("subject"), request.args.get("body")
     )
 

atst/routes/portfolios/invitations.py

@@ -6,7 +6,7 @@ from atst.domain.exceptions import AlreadyExistsError
 from atst.domain.invitations import PortfolioInvitations
 from atst.domain.portfolios import Portfolios
 from atst.models import Permissions
-from atst.queue import queue
+from atst.jobs import send_mail
 from atst.utils.flash import formatted_flash as flash
 from atst.utils.localization import translate
 import atst.forms.portfolio_member as member_forms
@@ -16,7 +16,7 @@ def send_portfolio_invitation(invitee_email, inviter_name, token):
     body = render_template(
         "emails/portfolio/invitation.txt", owner=inviter_name, token=token
     )
-    queue.send_mail(
+    send_mail.delay(
         [invitee_email],
         translate("email.portfolio_invite", {"inviter_name": inviter_name}),
         body,