[WIP] My account section : home, profile edition and password change [Clean]

Clean version of https://github.com/Sylius/Sylius/pull/99

This PR refers to the following discussion : #88
A RFC describes the features and the implementation here : https://github.com/Sylius/Sylius/wiki/%5BRFC%5D-My-account-section

Two features of the my account section will be released with this PR :
* profile edition
* password change