Update bundle docs to follow best practices

[wouterj]

http://symfony.com/doc/current/cookbook/bundles/best_practices.html#installation-instructions

• [x] block #794
• [x] content #810
• [x] core #811
• [x] menu #808
• [x] phpcr_odm #807
• [x] routing #804
• [ ] routing_auto
• [x] seo #805
• [x] sonata_phpcr_admin_integration
• [x] tree_browser #806

[dbu]

indeed. so we should change our examples to use the AppBundle and shorter service names.

i propose we go by bundle chapter to avoid a huge single pull request that will be hard to merge.

[dbu]

routing auto doc needs to be written