Changes on the Router to avoid array_diff, array_keys and other inneficient array_ functions.
This is a "recommit" to respect Symfony Contribution rules
In routing files, import statements allow an optional "type" option to hint the resources' type (e.g. for ambiguous file extensions). This adds the same type option to the FrameworkExtension config, which defines the main routing resource.
This reverts commit f53080860a.
Revert "[Router] config fixes"
This reverts commit 51beecc6f2.
Revert "moved duplicated files to a new Config component"
This reverts commit a8ec9b27f0.