create new frame-type useful for labeled-logs and maybe other things

[gabor]

WIP

related to https://github.com/grafana/grafana/pull/47346

we are trying to create a frame-type that is useful for data that uses a separate, single labels-field, where all the label-names-and-values for the given "row" are encoded.

See also: https://github.com/grafana/grafana/blob/main/public/app/features/live/data/StreamingDataFrame.test.ts#L670. This is the format that grafana live will use internally when streaming form influx line protocol or prometheus format

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