fix(dex): Add correct dex service name and mux

[sven-urbanski-freiheit-com]

• The dex service is called kuberpult-dex
• The dex routes are now added to the mux which is served -> before they were implicitly added to http.DefaultServeMux but the mux which was served was http.NewServeMux()

Now when you try to access any of

		"/environments",
		"/environments/",
		"/environment-groups",
		"/environment-groups/",
		"/release",

if c.DexEnabled you should get forwarded.

For setup of the values.yaml (I only paste dex-relevant stuff, of course you'd also need a manifest repo connected etc.):

auth:
  dexAuth:
    baseURL: https://kuberpult.example.com
    clientId: sample-id-kuberpult-dex
    clientSecret: sample-secret-kuberpult-dex
    enabled: true
    installDex: true
    policy_csv: |
      p, role:Developer, CreateLock, *:*, *, allow
      g, your-github-org:your-github-team, role:Developer
    scopes: "openid, groups, email, profile, federated:id"
dex:
  config:
    connectors:
    - config:
        clientID: GITHUB_OAUTH_CLIENT_ID
        clientSecret: GITHUB_OAUTH_CLIENT_SECRET
        orgs:
        - name: your-github-org
        redirectURI: https://kuberpult.example.com/dex/callback
      id: github
      name: GitHub
      type: github
    issuer: https://kuberpult.example.com/dex
    staticClients:
    - id: sample-id-kuberpult-dex
      name: kuberpult
      redirectURIs:
      - https://kuberpult.example.com/callback
      secret: sample-secret-kuberpult-dex
    storage:
      type: memory

Remark:

• The scopes have to be a string with comma seperated values
• The clientID in dex.config.connectors[0].config.clientID is used for authentication with e.g. GitHub
• The clientID in auth.dexAuth.clientID is another one which matches the staticClient at dex.staticClients[0].id
• The same goes for the secrets - I stumbled over this.

Now with this setup replacing:

• kuberpult.example.com with your hostname
• GITHUB_OAUTH_CLIENT_ID with your oauth client ID created in your GitHub Org
• GITHUB_OAUTH_CLIENT_SECRET with your oauth client secret created in your GitHub Org
• your-github-org with the name of your github-org
  

It should also work for you.

And of course you need to switch the image in frontend-service to the version of this PR.
Which was a little tricky for testing as frontend.tag option is not allowed the values anymore. I just patched the deployment in my cluster afterwards manually.

Afterwards access kuberpult.example.com/environments -> you will get redirected to GitHub login:

Then a cookie will be set:

Which also contains the relevant information:

Originally opened by @jdvgh
Closes #1510

[jdvgh]

It looks like the failing step is something uncorrelated to my changes from the logs of the CI.

[sven-urbanski-freiheit-com]

@jdvgh should I merge it as it is now?
The integration test was successful

[jdvgh]

Yeah, go ahead!🙂