Fluent-bit: Add log_to_metrics filter plugin

[jcdauchy-moodys]

Is your feature request related to a problem? Please describe.

Really useful plugin to extract metrics from logs:

https://docs.fluentbit.io/manual/pipeline/filters/log_to_metrics

Describe the solution you'd like

It could be used with RemoteWrite plugin or other output plugins.

Thanks

Additional context

No response

[Athishpranav2003]

@jcdauchy-moodys https://github.com/fluent/fluent-operator/blob/0f632a794feb743b890ba1cde13145ccb1781dd3/docs/best-practice/custom-plugin.md this might be helpful for your case

@cosmo0920 will it be useful to add the interface for this plugin? Adding the plugin to codebase is simply adding the interface but not sure if its indeed necessary tho. If its needed maybe i can do this one quick

[cosmo0920]

To use fluent bit plugins, we might need to create a map (or interface?) to use actual parameters for plugins. For log_to_metrics filter plugin, we defined the config map: https://github.com/fluent/fluent-bit/blob/master/plugins/filter_log_to_metrics/log_to_metrics.c#L965-L1052

For adding to build metrics type of pipelines, this plugin would be useful because it's only one plugin to bypass/translate logs type of pipelines into metrics type of pipelines.

[Athishpranav2003]

Oh ok Then i will go ahead and work on this then