Automate the setup of github identity provider with internal keycloak

[tolusha]

What does this PR do

Automate the setup of github identity provider with internal keycloak

Reference issue

eclipse-che/che#18238

To provision github identity provider the following secret should be created:

kind: Secret
apiVersion: v1
metadata:
  name: github-credentials
  namespace: che
  labels:
    app.kubernetes.io/part-of: che.eclipse.org
    app.kubernetes.io/component: keycloak-secret
  annotations:
    che.eclipse.org/github-oauth-credentials: "true"
    che.eclipse.org/mount-as: env
    che.eclipse.org/githubId_env-name: GITHUB_CLIENT_ID
    che.eclipse.org/githubSecret_env-name: GITHUB_SECRET
data:
  githubId: <..>
  githubSecret: <..>
type: Opaque

[tolusha]

/retest

[openshift-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: davidfestal, tolusha
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[openshift-ci-robot]

New changes are detected. LGTM label has been removed.

[tolusha]

/retest