Adding support for JWKS-based token validation and token attribute mapping (#151)

[Starefossen]

Adds support for JWKS-based token validation (nokia#150) and also extracting token attributes as HTTP headers (besides the X-Userinfo header)

[Starefossen]

@cristichiru will you be accepting this pull request if I resolve the merge conflicts?

[Starefossen]

@jmdacruz I have proposed this change for the revomatico fork since that seams to be the one that is most maintained.

[cristichiru]

@Starefossen of course!

[hanlaur]

@Starefossen You could check #2 if it covers your JWT validation and header injection use case. Quite a timing coincidence!

[nachtfisch]

for me that did the trick. both JWKS based validation from discovery endpoint as well as header mapping works.

Using a config like this.

_format_version: "1.1"

services:
 - name: mock-service
   url: http://mockbin.org/request
   path: /
   tags:
   - example
   routes:
    - name: mock-route
      methods:
      - GET      
      paths: ["/mock"] 
plugins:
- name: oidc
  config:
    client_id: "dummy"
    client_secret: "dummy"
    discovery: "redacted"
    unauth_action: deny
    # bearer_only: "yes"
    bearer_jwt_auth_enable: "yes"
    bearer_jwt_auth_allowed_auds: ["redacted"]
  enabled: true
  protocols:
  - grpc
  - grpcs
  - http
  - https    

[cristichiru]

So, can we close this?