Add user documentation

[sstok]

No description provided.

[cordoval]

are there examples on how to create the filters for those grids? Thanks @sstok 👴

[sstok]

Filtering is not completely supported at the moment :) the datagrid receives Iterable data in order to render, so the filtering happens before its passed to the datagrid.

For the Symfony integration Bundle I'm planning on using RollerworksSearch.

[sstok]

The Datagrid is greatly refactored and improved, so I feel it's time to start working on the documentation. Once v0.10 is released 😊