Move symfony cache component

Fix #170, Replace #177

Depends on https://github.com/FriendsOfSymfony/FOSHttpCache/pull/145

*TODO*
* [ ] Wrap up https://github.com/FriendsOfSymfony/FOSHttpCache/pull/145, tag a version and up the required version in composer.json
* [ ] Documentation (see also #178 but note that things changed since then)
I [did it in eZ Publish](https://github.com/ezsystems/ezpublish-kernel/blob/master/eZ/Bundle/EzPublishCoreBundle/HttpCache.php#L118-L123), but I'll update the kernel as soon as this is merged :-P