[OptionsResolver] Choose policy on unknown options

Hi,

This commit adds the possibility to choose a policy on unknown options :
- required : like before, throw exception (default to keep BC)
- remove : remove options and do not throw exception
- ignore : keep options and do not throw exception

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |