feat: oidc authentication and session management

[kushsharma]

• on successful authentication, a cookie with sid is set
• on successful authentication, a jwt token in response headers is set via x-user-token containing details related to the user and its org
• jwt public keys are available at /jwks.json
• check examples/auth directory for usage
• feat(shield): support for oidc authentication proton#253

Additional config added in app section

  # configuration to allow authentication in shield
  authentication:
    # to use shield as session store
    session:
      # both of them should be 32 chars long
      # hash helps identify if the value is tempered with
      hash_secret_key: "hash-secret-should-be-32-chars--"
      # block helps in encryption
      block_secret_key: "block-secret-should-be-32-chars-"
    # once authenticated, server responds with a jwt with user context
    token:
      # generate key file via "./shield server gen rsa"
      rsa_path: ./temp/rsa
      iss: "http://localhost.shield"
    # external host used for oidc redirect uri, e.g. http://localhost:7400/admin/v1beta1/auth/callback
    oidc_callback_host: http://localhost:7400/admin/v1beta1/auth/callback
    # oidc auth server configs
    oidc_config:
      google:
        client_id: "xxxxx.apps.googleusercontent.com"
        client_secret: "xxxxx"
        issuer_url: "https://accounts.google.com"

[coveralls]

Pull Request Test Coverage Report for Build 4658548589

• 52 of 317 (16.4%) changed or added relevant lines in 9 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-1.5%) to 56.005%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
internal/api/v1beta1/v1beta1.go	0	13	0.0%
cmd/serve.go	0	16	0.0%
cmd/server.go	14	30	46.67%
internal/store/postgres/flow_repository.go	0	18	0.0%
internal/store/postgres/session_repository.go	0	18	0.0%
internal/api/v1beta1/user.go	24	47	51.06%
internal/store/postgres/organization_repository.go	0	48	0.0%
internal/api/v1beta1/authenticate.go	13	126	10.32%

Totals
Change from base Build 4496853566:	-1.5%
Covered Lines:	4696
Relevant Lines:	8385

---

💛 - Coveralls

[pyadav]

To generate key file, command is

./shield server keygen

[pyadav]

Also, I think example dir does not contains all files
Am I missing something?