[extension/leader elector] Initial implementation for the extension leader elector - basic structure

[rakesh-garimella]

Description

This extension could be used to run multiple receivers in HA mode. The receiver which has successfully acquired the lease becomes active and thus becomes leader.

The extension uses k8s.io/client-go/tools/leaderelection to perform leader election. The component that owns the lease becomes the leader and runs the function defined in onStartedLeading. If the leader loses the lease, it runs the function defined in onStoppedLeading, stops its operation, and waits to acquire the lease again.

The config would like this:

receivers:
  my_awesome_reciever:
    leader_elector: leader_elector
exporters:
  debug:
    verbosity: detailed
extensions:
  leader_elector:
    auth_type: kubeConfig
    lease_name: foo
    lease_namespace: default

service:
  extensions: [leader_elector]
  pipelines:
    metrics:
      receivers: [my_awesome_receiver]
      exporters: [debug]
  telemetry:
    logs:
      level: debug

Link to tracking issue

Fixes
#34460

Testing

unit tests have been added

Documentation

README file has been added