Add OAuth2 to ClusterLogForwarder

1. Proposed title of this feature request

Add OAuth2 option to ClusterLogForwarder 

2. What is the nature and description of the request?

The current limitation lies in the inability of the ClusterLogForwarder to authenticate requests using OAuth 2.0. 

3. Why does the customer need this? (List the business requirements here)

The customer is utilising an external observability stack that is comprised of Grafana and Loki to monitor and analyse logs from their OpenShift environment. To facilitate the aggregation and forwarding of logs from OpenShift to their observability stack, the customer is leveraging the OpenShift ClusterLogForwarder.

As a workaround, the customer has implemented a proxy solution [1] that adds OAuth 2.0 support for log forwarding.

The customer has expressed the need for OAuth 2.0 validation to be natively integrated into the OpenShift ClusterLogForwarder's capabilities, thereby streamlining the log forwarding process and eliminating the need for an external proxy.

[1] Token Refresher Proxy on GitHub

4. List any affected packages or components.

openshift-logging