[Metrics UI] Add Charts to Alert Conditions

- Reorganize files under public/alerting
- Change Metrics Explorer API to force interval
- Add charts to expression rows
- Allow expression rows to be collapsable
- Adding sum aggregation to Metrics Explorer for parity

Author: simianhacker

x-pack/plugins/infra/common/http_api/metrics_explorer/index.ts renamed to x-pack/plugins/infra/common/http_api/metrics_explorer.ts

@@ -13,6 +13,7 @@ export const METRIC_EXPLORER_AGGREGATIONS = [
   'cardinality',
   'rate',
   'count',
+  'sum',
 ] as const;
 
 type MetricExplorerAggregations = typeof METRIC_EXPLORER_AGGREGATIONS[number];
@@ -54,6 +55,7 @@ export const metricsExplorerRequestBodyOptionalFieldsRT = rt.partial({
   afterKey: rt.union([rt.string, rt.null, rt.undefined]),
   limit: rt.union([rt.number, rt.null, rt.undefined]),
   filterQuery: rt.union([rt.string, rt.null, rt.undefined]),
+  forceInterval: rt.boolean,
 });
 
 export const metricsExplorerRequestBodyRT = rt.intersection([

x-pack/plugins/infra/common/saved_objects/metrics_explorer_view.ts

@@ -35,6 +35,9 @@ export const metricsExplorerViewSavedObjectMappings: {
       },
       options: {
         properties: {
+          forceInterval: {
+            type: 'boolean',
+          },
           metrics: {
             type: 'nested',
             properties: {