Elasticsearch: Implement processing of logs query results in backend (#63647)

* Elasticsearch: Add processing of logs query to backend

* Add and fix tests

* Add snapshot tests

* Fix test in ES client

* Small updates, remove redundant logic

* Refactor setPreferredVisType to improve readability

pkg/tsdb/elasticsearch/querydata_test.go

@@ -37,15 +37,22 @@ func (rt *queryDataTestRoundTripper) RoundTrip(req *http.Request) (*http.Respons
 }
 
 // we setup a fake datasource-info
-func newFlowTestDsInfo(body []byte, statusCode int, reuestCallback func(req *http.Request) error) *es.DatasourceInfo {
+func newFlowTestDsInfo(body []byte, statusCode int, requestCallback func(req *http.Request) error) *es.DatasourceInfo {
 	client := http.Client{
-		Transport: &queryDataTestRoundTripper{body: body, statusCode: statusCode, requestCallback: reuestCallback},
+		Transport: &queryDataTestRoundTripper{body: body, statusCode: statusCode, requestCallback: requestCallback},
 	}
+
+	configuredFields := es.ConfiguredFields{
+		TimeField:       "testtime",
+		LogMessageField: "line",
+		LogLevelField:   "lvl",
+	}
+
 	return &es.DatasourceInfo{
 		ESVersion:                  semver.MustParse("8.5.0"),
 		Interval:                   "Daily",
 		Database:                   "[testdb-]YYYY.MM.DD",
-		TimeField:                  "testtime",
+		ConfiguredFields:           configuredFields,
 		TimeInterval:               "1s",
 		URL:                        "http://localhost:9200",
 		HTTPClient:                 &client,