SQL Datasources: Move database setting to jsonData (#58649)

* Datasource settings: Add deprecation notice for database field

* SQL Datasources: Migrate from settings.database to settings.jsonData.database

* Check jsonData first

* Remove comment from docs

pkg/tsdb/sqleng/sql_engine.go

@@ -66,6 +66,7 @@ type JsonData struct {
 	Encrypt             string `json:"encrypt"`
 	Servername          string `json:"servername"`
 	TimeInterval        string `json:"timeInterval"`
+	Database            string `json:"database"`
 }
 
 type DataSourceInfo struct {