Introduce TSDB service (#31520)

* Introduce TSDB service

Signed-off-by: Arve Knudsen <arve.knudsen@gmail.com>

Co-authored-by: Erik Sundell <erik.sundell87@gmail.com>
Co-authored-by: Will Browne <will.browne@grafana.com>
Co-authored-by: Torkel Ödegaard <torkel@grafana.org>
Co-authored-by: Will Browne <wbrowne@users.noreply.github.com>
Co-authored-by: Zoltán Bedi <zoltan.bedi@gmail.com>

pkg/services/alerting/interfaces.go

@@ -5,6 +5,7 @@ import (
 	"time"
 
 	"github.com/grafana/grafana/pkg/models"
+	"github.com/grafana/grafana/pkg/tsdb/tsdbifaces"
 )
 
 type evalHandler interface {
@@ -59,5 +60,5 @@ type ConditionResult struct {
 
 // Condition is responsible for evaluating an alert condition.
 type Condition interface {
-	Eval(result *EvalContext) (*ConditionResult, error)
+	Eval(result *EvalContext, requestHandler tsdbifaces.RequestHandler) (*ConditionResult, error)
 }