Add support for --complete

[greg0ire]

When using orm:schema-tool:update together with --complete, all assets not described by the current metadata is dropped.

This is an issue when using doctrine/migrations, because not using that option is deprecated, and because when it is used, the table that holds the migrations is dropped as well since it is not described by ORM metadata.

A solution to that is configuring an asset filter that filters out the metadata table except when running commands inside the migrations namespace.

How can I test this?

composer config repositories.greg0ire vcs https://github.com/greg0ire/DoctrineMigrationsBundle
composer require doctrine/doctrine-migrations-bundle "dev-complete-compat as 3.3.0"