[OptionsResolver] Implemented policies for treating unknown/missing options

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | yes
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #7979, replaces #9754
| License       | MIT
| Doc PR        | symfony/symfony-docs#3731

replacement for #10574 which was closed by accident
No, I'm just talking about this PR. We need to measure the influence with a moderately big form. Do you have time for that?