New component: receiver/lokireceiver

[mar4uk]

The purpose and use-cases of the new component

The Loki receiver implements the Loki push api as specified here. It allows Promtail instances to specify the open telemetry collector as their lokiAddress.

This issue is the reincarnation of #9800

Example configuration for the component

receivers:
  loki:
    protocols:
      http:
        endpoint: 0.0.0.0:3500
      grpc:
        endpoint: 0.0.0.0:3600    
   # Label map to add to every log line sent to the push API
    labels:
      [ <labelname>: <labelvalue> ... ]   

labels could be converted to Log Record Attributes

Telemetry data types supported

Logs

Is this a vendor-specific component?

• This is a vendor-specific component
• If this is a vendor-specific component, I am proposing to contribute this as a representative of the vendor.

Sponsor (optional)

No response

Additional context

The previous implementation of promtail receiver failed because it had pull and push implementation. Pull implementation required importing Loki, which led to bringing a lot of dependencies and vulnerabilities to the collector.
Such amount of dependencies is difficult to maintain. That's why the decision to remove promtail receiver was made (#18524)

In this proposal, I suggest implementing only the push mechanism.
It will cover community request to send loki logs to the collector

[kovrus]

I can sponsor this component.

[github-actions]

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[fbuetler]

As it is completed, in what version is this going to be available?