Explore: Adds Loki explore query editor (#21497)

* Explore: updates grafana-data explore query field props with explore mode

* Explore: updates query row to pass down explore mode to query fields

* Explore: adds LokiExploreQueryEditor

* Explore: updates loki query field form to render children

* Explore: adds loki explore extra field component

* Explore: adds extra field element to loki query field form

* Explore: updates loki explore query editor to use extra field element

* Explore: moves ExploreMode to grafana-data

* Explore: updates query row limit string

* Explore: adds maxLines to DataQuery

* Explore: adds maxLines to loki datasource runRangeQueryWithFallback

* Explore: adds onChangeQueryLimit to LokiExploreQueryEditor

* Explore: updates loki explore query editor to render extra field only in logs mode

* Explore: fixes query limits for live and legacy queries

* Explore: fixes result processor max lines limit in get logs result

* Explore: fixes Loki datasource limit test

* Explore: removes unnecessary ExploreMode from Loki language provider

* Explore: fixes formatting

* Explore: updates grafana-data datasource types - replaces strings with explore mode enum

* Explore: updates loki explore query field props to take ReactNode

* Explore: updates the way we calculate loki query lines limit to fall back to 0 lines on negative or invalid input instead of datasource maxLines

* Explore: updates result processor get logs result method to avoid counting invalid/negative line limits

* Explore: updates loki result transformer to process only an appropriate slice of a result instead of an entire one

* Explore: adds a method for query limit preprocessing/mapping

* Explore: updates loki datasource run range query with fallback method to use options.maxDataPoints in dashboards

* Explore: removes unnecessary maxlineslimt from getLogsResult in resultProcessor

* Explore: moves line limit to metadata

* Explore: adds an ability to specify input type of extra field

* Explore: updates LokiExploreQueryEditor - adds an input type

* Explore: updates LokiExploreQueryEditor to run queries when maxLines is positive

* Explore: fixes failing import of ExploreMode

* Explore: fixes reducers test imports formatting

* Explore: updates Loki extra field with min value set to 0

* Explore: exports LokiExploreExtraFieldProps

* Explore: adds render test of LokiExploreQueryEditor

* Explore: adds LokiExploreQueryEditor snapshot

* Explore: updates LokiExploreQueryEditor onChangeQueryLimit method to prevent it from running when query input is empty - fixes cheatsheet display issue

* Explore: updates Loki editor snapshots

* Explore: fixes typo in test set name in LokiExploreQueryEditor

* Explore: adds a render test of LokiExploreExtraField

* Explore: fixes typo in LokiExploreQueryEditor

* Explore: updates LokiExploreQueryEditor snapshot due to timezone issues

* Explore: updates LokiExploreExtraField to export both functional component and a version using memo

* Explore: updates LokiExploreQueryEditor to export both functional component and memoized function

* Explore: updates LokiExploreQueryEditor - removes unnecessary react fragment

* Explore: updates LokiExploreQueryEditor snapshot

* Explore: adds LokiExploreQueryEditor tests for different explore mode cases

* Explore: fixes Loki datasource and result transformer

* Explore: updates LokiExploreQueryEditor snapshot

* Explore: updates LokiExploreQueryEditor tests and test setup

* Explore: updates LokiExploreQueryEditor - refactors component

* Explore: updates LokiExploreQueryEditor to use default import from LokiExploreExtraField

* Explore: updates LokiExploreQueryEditor snapshot

* Explore: fixes formatting

* Explore: updates LokiExploreQueryEditor max lines change

* Explore: updates LokiExploreQueryEditor tests checking ExtraFieldElement

* Explore: adds mock loki datasource to LokiExploreQueryEditor

* Explore: updates LokiExploreQueryEditor test mock - adds language provider

* Explore: updates LokiExploreQueryEditor snapshot

* Explore: updates Loki ResultTransformer to filter out rows on limit - logic to be moved into a component with new form styles

* Explore: updates LokiExploreQueryEditor tests

public/app/core/logs_model.ts

@@ -353,11 +353,17 @@ export function logSeriesToLogsModel(logSeries: DataFrame[]): LogsModel | undefi
   }
 
   const limits = logSeries.filter(series => series.meta && series.meta.limit);
+  const limitValue = Object.values(
+    limits.reduce((acc: any, elem: any) => {
+      acc[elem.refId] = elem.meta.limit;
+      return acc;
+    }, {})
+  ).reduce((acc: number, elem: any) => (acc += elem), 0);
 
   if (limits.length > 0) {
     meta.push({
       label: 'Limit',
-      value: `${limits[0].meta.limit} (${deduplicatedLogRows.length} returned)`,
+      value: `${limitValue} (${deduplicatedLogRows.length} returned)`,
       kind: LogsMetaKind.String,
     });
   }