[FOSUserBundle] Add user reset password functionality to login page

Hi all,

A little PR for adding the possibility for a customer to reset his password.
I add some FOSUserBundle template override to match sylius ones.
Needed for my own project, maybe this could interest you ?

Waiting comments ;)

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | 
| License       | MIT
| Doc PR        | 

![login](https://cloud.githubusercontent.com/assets/1230954/3352022/09a2fd5c-fa2e-11e3-8600-59fb7d72c023.jpg)
![request](https://cloud.githubusercontent.com/assets/1230954/3352025/09aa8aea-fa2e-11e3-86d6-1f2d03d6eb5c.jpg)
![request-confirmation](https://cloud.githubusercontent.com/assets/1230954/3352023/09a5305e-fa2e-11e3-9cb3-bf9b3f82cb1c.jpg)
![reset](https://cloud.githubusercontent.com/assets/1230954/3352024/09a72b20-fa2e-11e3-98ae-d9739f00ce20.jpg)
![reset-confirmation](https://cloud.githubusercontent.com/assets/1230954/3352026/09ac515e-fa2e-11e3-9b8a-0f25906cd13b.jpg)