TimeSeries: Add support for negative Y and constant transform (#44774)

* add negative y config

* Handle negative y and constant transform in Timeseries panel

* Typechecks

* Add migration from old graph panel

* Docs update

* Revert "Add migration from old graph panel"

This reverts commit 33b5a90b66.

* Revert VizLegendItem changes

* Automatically separate positive and negative stacks within a group

* Update packages/grafana-ui/src/components/VizLegend/VizLegend.story.tsx

* Remove SeriesLabel component

* Update docs/sources/visualizations/time-series/_index.md

Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>

* Update docs/sources/visualizations/time-series/_index.md

Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>

* Leftover reverts

* Don't crate bands (for now0 for negative -y stack

* Add docs note about transform being only available as an override

* Fill negative bands in reversed direction

Co-authored-by: Ryan McKinley <ryantxu@gmail.com>
Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>

public/app/plugins/panel/timeseries/config.ts

@@ -16,6 +16,7 @@ import {
   VisibilityMode,
   StackingMode,
   GraphTresholdsStyleMode,
+  GraphTransform,
 } from '@grafana/schema';
 
 import { graphFieldOptions, commonOptionsBuilder } from '@grafana/ui';
@@ -181,6 +182,29 @@ export function getGraphFieldConfig(cfg: GraphFieldConfig): SetFieldConfigOption
         });
 
       commonOptionsBuilder.addStackingConfig(builder, cfg.stacking, categoryStyles);
+
+      builder.addSelect({
+        category: categoryStyles,
+        name: 'Transform',
+        path: 'transform',
+        settings: {
+          options: [
+            {
+              label: 'Constant',
+              value: GraphTransform.Constant,
+              description: 'The first value will be shown as a constant line',
+            },
+            {
+              label: 'Negative Y',
+              value: GraphTransform.NegativeY,
+              description: 'Flip the results to negative values on the y axis',
+            },
+          ],
+          isClearable: true,
+        },
+        hideFromDefaults: true,
+      });
+
       commonOptionsBuilder.addAxisConfig(builder, cfg);
       commonOptionsBuilder.addHideFrom(builder);