Remove controller resolver auto mapping option

[bobvandevijver]

From #1924: version 4.0 should fully remove the doctrine.orm.controller_resolver.auto_mapping option.

Upgrade notes content:

### `doctrine.orm.controller_resolver.auto_mapping` option has been removed

The `doctrine.orm.controller_resolver.auto_mapping` only accepted `false` as value since 3.0 and is now removed.

[greg0ire]

@bobvandevijver you can proceed with this and other PRs :)