Usability: It would be nice if the PublishLabelOptions could be folded into the Plot class

[tlisonbee]

PublishLabelOptions would make more sense as part of the Plot class. It would make the API more closely model the SignalFx UI (vs. modeling the less user friendly Sfx REST API).

Currently, PublishLabelOptions looks like this but all of those options are more related to the Plot they are modifying.

        TimeSeriesChart() \
            .with_name("Lambda " + function_name + " Invocations") \
            .with_description(description)
            .with_default_plot_type(PlotType.column_chart) \
            .with_chart_legend_options("sf_metric", show_legend=True)
            .with_publish_label_options(
            PublishLabelOptions(
                label='Invocations',
                palette_index=PaletteColor.green
            ),
            PublishLabelOptions(
                label='Duration',
                palette_index=PaletteColor.gray,
                y_axis=1,
                plot_type=PlotType.line_chart,
                value_unit='Millisecond'
            )
        )
            .with_axes([AxisOption(label="Count", min=0), AxisOption(label="Latency", min=0)])
            .with_program(
            Program(
                Plot(
                    assigned_name="A",
                    signal_name="Invocations",
                    filter=And(
                        Filter("FunctionName", function_name),
                        Filter("namespace", "AWS/Lambda"),
                        Filter("stat", "sum")
                    ),
                    rollup=RollupType.sum,
                    fx=[Sum(by=["aws_account_id", "FunctionName"])],
                    label="Invocations"),
                Plot(
                    assigned_name="B",
                    signal_name="Duration",
                    filter=And(
                        Filter("FunctionName", function_name),
                        Filter("namespace", "AWS/Lambda"),
                        Filter("stat", "mean")
                    ),
                    rollup=RollupType.max,
                    fx=[Sum(by=["aws_account_id", "FunctionName"])],
                    label="Duration")

            )
        )