[WIP] Add behavior tests

- [x] Add configuration example to use a remote selenium server
- [x] Add register feature
- [x] Add captcha feature
- [x] Add guest access feature
- [x] Add change password features
- [ ] Add log in trough authentication provider features
- [x] ~~Add selenium server in vendors.php script to be able to run locally BDD tests directly ?~~
- [x] Update `builder.php` script to remove new dev files