Introduce QueryParts object in QueryBuilder

Author: BenMorel

UPGRADE.md

@@ -1,6 +1,8 @@
 # Upgrade to 3.0
 
-## BC BREAK: `QueryBuilder::insert()`, `update()` and `delete()` signatures changed
+## BC BREAK: `QueryBuilder::add()`, `QueryBuilder::getQueryPart()`, `resetQueryPart()` and `resetQueryParts()` are removed, `getQueryParts()` is now `@internal`.
+
+## BC BREAK: `QueryBuilder::insert()`, `update()` and `delete()` signatures changed.
 
 These methods now require the `$table` parameter, and do not support aliases anymore.