Add alternative SQL EXPLAIN tool to doc

doc/development/database/index.md

@@ -3,8 +3,7 @@
 ## Tooling
 
 - [Understanding EXPLAIN plans](../understanding_explain_plans.md)
-- [explain.depesz.com](https://explain.depesz.com/) for visualizing the output
-  of `EXPLAIN`
+- [explain.depesz.com](https://explain.depesz.com/) or [explain.dalibo.com](https://explain.dalibo.com/) for visualizing the output of `EXPLAIN`
 - [pgFormatter](http://sqlformat.darold.net/) a PostgreSQL SQL syntax beautifier
 
 ## Migrations

doc/development/understanding_explain_plans.md

@@ -657,7 +657,7 @@ different queries. The only _rule_ is that you _must always measure_ your query
 and related tools such as:
 
 - [`explain.depesz.com`](https://explain.depesz.com/).
-- [Pev](http://tatiyants.com/postgres-query-plan-visualization/).
+- [`explain.dalibo.com/`](https://explain.dalibo.com/).
 
 ## Producing query plans