Add documentation for JMS Serialiser and DatagridBundle
Add documentation for JMS Serialiser and DatagridBundle

`SonataPageBundle` uses `Pager` class from `DatagridBundle`. In order to have correct serialized output this config should be added to `config.yml` (copied from [config](https://github.com/sonata-project/sandbox/blob/2.3/app/config/config.yml) of Sonata Project sandbox)
Dunduro/SonataPageBundle,Th3Mouk/SonataPageBundle,grimpows/SonataPageBundle,Aylarius/SonataPageBundle,Dunduro/SonataPageBundle,sonata-project/SonataPageBundle,Dunduro/SonataPageBundle,Th3Mouk/SonataPageBundle,Aylarius/SonataPageBundle,grimpows/SonataPageBundle,Aylarius/SonataPageBundle,grimpows/SonataPageBundle,Dunduro/SonataPageBundle,grimpows/SonataPageBundle,Aylarius/SonataPageBundle,Aylarius/SonataPageBundle,Th3Mouk/SonataPageBundle,Th3Mouk/SonataPageBundle,grimpows/SonataPageBundle,Dunduro/SonataPageBundle,sonata-project/SonataPageBundle