lib/popcorn: introduce Router::use_after service
lib/popcorn: introduce Router::use_after service

So the user can force some middlewares to be called after the other handlers.

Signed-off-by: Alexandre Terrasa <b30f4169e054ee7b8c243480bcfcef62416f3b08@moz-code.org>

privat/nit,jpcaissy/nit,jpcaissy/nit,jcbrinfo/nit,ventilooo/nit,privat/nit,privat/nit,ventilooo/nit,jpcaissy/nit,ventilooo/nit,jcbrinfo/nit,privat/nit,ventilooo/nit,jcbrinfo/nit,ventilooo/nit,jcbrinfo/nit,jcbrinfo/nit,ventilooo/nit,jcbrinfo/nit,jcbrinfo/nit,jcbrinfo/nit,privat/nit,privat/nit,jpcaissy/nit,ventilooo/nit,jpcaissy/nit,jpcaissy/nit,jcbrinfo/nit,privat/nit,privat/nit,jcbrinfo/nit,ventilooo/nit,jcbrinfo/nit,ventilooo/nit,privat/nit,jpcaissy/nit,ventilooo/nit,jpcaissy/nit,privat/nit