Alerting: Fetch all applied alerting configurations (#65728)

* WIP

* skip invalid historic configurations instead of erroring

* add warning log when bad historic config is found

* remove unused custom marshaller for GettableHistoricUserConfig

* add id to historic user config, move limit check to store, fix typo

* swagger spec

pkg/services/ngalert/api/tooling/definitions/alertmanager.go

@@ -54,6 +54,13 @@ import (
 //       400: ValidationError
 //       404: NotFound
 
+// swagger:route GET /api/alertmanager/grafana/config/history alertmanager RouteGetGrafanaAlertingConfigHistory
+//
+// gets Alerting configurations that were successfully applied in the past
+//
+//     Responses:
+//       200: GettableHistoricUserConfigs
+
 // swagger:route DELETE /api/alertmanager/grafana/config/api/v1/alerts alertmanager RouteDeleteGrafanaAlertingConfig
 //
 // deletes the Alerting config for a tenant
@@ -229,6 +236,13 @@ type AlertManagerNotReady struct{}
 // swagger:model
 type MultiStatus struct{}
 
+// swagger:parameters RouteGetGrafanaAlertingConfigHistory
+type RouteGetGrafanaAlertingConfigHistoryParams struct {
+	// Limit response to n historic configurations.
+	// in:query
+	Limit int `json:"limit"`
+}
+
 // swagger:parameters RoutePostTestGrafanaReceivers
 type TestReceiversConfigParams struct {
 	// in:body
@@ -633,6 +647,20 @@ func (c *GettableUserConfig) GetGrafanaReceiverMap() map[string]*GettableGrafana
 	return UIDs
 }
 
+type GettableHistoricUserConfig struct {
+	ID                      int64                     `yaml:"id" json:"id"`
+	TemplateFiles           map[string]string         `yaml:"template_files" json:"template_files"`
+	TemplateFileProvenances map[string]Provenance     `yaml:"template_file_provenances,omitempty" json:"template_file_provenances,omitempty"`
+	AlertmanagerConfig      GettableApiAlertingConfig `yaml:"alertmanager_config" json:"alertmanager_config"`
+	LastApplied             *strfmt.DateTime          `yaml:"last_applied,omitempty" json:"last_applied,omitempty"`
+}
+
+// swagger:response GettableHistoricUserConfigs
+type GettableHistoricUserConfigs struct {
+	// in:body
+	Body []GettableHistoricUserConfig
+}
+
 type GettableApiAlertingConfig struct {
 	Config              `yaml:",inline"`
 	MuteTimeProvenances map[string]Provenance `yaml:"muteTimeProvenances,omitempty" json:"muteTimeProvenances,omitempty"`