Add cgroup plugin

[vlasad]

Required for all PRs:

• CHANGELOG.md updated
• Sign CLA (if not already signed)
• README.md updated (if adding a new plugin)

[sebito91]

👍 from us!

[Will-Beninger]

👍 from us! I've pulled in your changes and have already started testing the plugin.

No issues so far and would love to see it pulled into 1.0.1 beta version!

[sebito91]

Any idea when we can merge this? Waiting for v.1.0.0?

[sparrc]

Hi @sebito91, sorry for the delay but I've been very busy with work on the logparser plugin. I have been trying to concentrate on that but can hopefully get to these PRs by the middle of the week.

[Will-Beninger]

@sparrc Appreciate it! My workaround at the moment to integrate cgroups and then our own plugins is quite ugly at the moment. haha

[sparrc]

Looks good on the whole, but are the flush_scope and writeWithBatches changes still necessary considering #1321?

[sparrc]

@vlasad bump, is the flush_scope argument still necessary? Seems like it is a duplication of the change @maksadbek is working on.

[vlasad]

It's not necessary already. I have removed it.

[sparrc]

Thank you @vlasad !

I hope you don't mind I made one small change: I've changed the external configuration to be "files" instead of "fields". To me "files" makes more sense, and since they were already internally called "files" I went ahead and changed it externally.

[vlasad]

It's OK. Also It's necessary to rename it in the README.md .