Replace insecure-oidc flag with the manual oidc config

[antgamdia]

Description of the change

For long time, we have been relying on the oidc autodiscovery feature, which is great. However, there are scenarios where it is not possible -the CSP case- . So, this PR is to stop recommending using --insecure-oidc-skip-issuer-verification in favor of a manual configuration, as follows:

   - --skip-oidc-discovery=true
   - --oidc-issuer-url=https://gaz.csp-vidm-prod.com
   - --login-url=https://console.cloud.vmware.com/csp/gateway/discovery
   - --redeem-url=https://console.cloud.vmware.com/csp/gateway/am/api/auth/token
   - --oidc-jwks-url=https://console.cloud.vmware.com/csp/gateway/am/api/auth/token-public-key?format=jwks

Instead of:

    - --insecure-oidc-skip-issuer-verification=true
    - --oidc-issuer-url=hhttps://console.cloud.vmware.com/csp/gateway/am/api

Benefits

No more "insecure" recommendations in our guides.

Possible drawbacks

A bit more lengthy, but it's necessary.

Applicable issues

• related Documentation to setup and configure Kubeapps 2.3.2 capabilities #2778

Additional information

I've also replaced the stating endpoints with the production ones. This way we have consistent docs in case of a user of the step-by-step wants to dig into the rest of the docs.

[absoludity]

Excellent, thanks Antonio. Couple of small copy-n-paste issues, but otherwise, great improvement (very happy to no longer recommend the ignore-insecure flag).