Create custom SSL context in Rasa OSS

[mvielkind]

Description of Problem:
When an action server is deployed with a custom SSL certificate the necessary CA certificates also need to be available within Rasa OSS.

Definition of Done:

[joejuzl]

So, status so far:

• I have created a PR (Add ability to point to a certificate in endpoints.yml #9118) that allows a local certificate file to be specified in endpoints.yaml
• I have tried it locally with test certificates:
  • I started the action server using the generated self-verified certificate.
  • When not supplying the cert to rasa I get exactly the same error as JPMC.
  • When adding the path to the same certificate running a custom action then works.
• HOWEVER, This is not exactly the same set-up as JPMC:
  • They use some kind of SSL termination between the k8s pods rather than providing a cert to the action server.
  • I don't know exactly what kind of certificate they are using.
  • @matthew @mariana is there a better way to realistically test this?

Also, we are currently in a minor freeze. This means there won't be any minor releases until 3.0 (around October).
This means we will have to release it as a micro, which is not ideal as it's not a bugifx... But as this seems v high prio it's the only option I can think of.

[m-vdb]

@joejuzl can this be closed?