Do not limit path for displaying images + fix imagine config

Found while testing https://github.com/symfony-cmf/BlockBundle/pull/125 that I broke the imagine configuration in a bundle standards refactor. This PR will fix this.

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | N/A
| License       | MIT
| Doc PR        | N/A