TestData: Support for csv files & csv content (#34674) (#34709)

* initial implementation of csv support for test data source

* CSV file & content scenarios working

* Removing categorical data

* fixing handler names

* Update pkg/tsdb/testdatasource/csv_data.go

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

* Update pkg/tsdb/testdatasource/csv_data.go

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

* Update pkg/tsdb/testdatasource/csv_data.go

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

* Update pkg/tsdb/testdatasource/csv_data.go

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

* Update pkg/tsdb/testdatasource/csv_data.go

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

* Update pkg/tsdb/testdatasource/csv_data.go

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

* Update pkg/tsdb/testdatasource/csv_data.go

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

* Fixed lint issues

* updated so it uses the same parsing

* more CSV tests

* lint fixes

* more lint

* lint

* support time field

* migrate manual entry to csv

* more test output

* more test output

* missing file

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>
Co-authored-by: Ryan McKinley <ryantxu@gmail.com>
(cherry picked from commit 987bffe482)

Co-authored-by: Torkel Ödegaard <torkel@grafana.org>

pkg/tsdb/testdatasource/testdata.go

@@ -11,6 +11,7 @@ import (
 	"github.com/grafana/grafana/pkg/plugins/backendplugin"
 	"github.com/grafana/grafana/pkg/plugins/backendplugin/coreplugin"
 	"github.com/grafana/grafana/pkg/registry"
+	"github.com/grafana/grafana/pkg/setting"
 )
 
 func init() {
@@ -19,6 +20,7 @@ func init() {
 
 type testDataPlugin struct {
 	BackendPluginManager backendplugin.Manager `inject:""`
+	Cfg                  *setting.Cfg          `inject:""`
 	logger               log.Logger
 	scenarios            map[string]*Scenario
 	queryMux             *datasource.QueryTypeMux