[Validator] Added Doctrine cache
feature #9892 [Validator] Added Doctrine cache (florianv)

This PR was merged into the 2.5-dev branch.

Discussion
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[Validator] Added Doctrine cache

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | yes
| Tests pass?   | yes
| Fixed tickets | https://github.com/symfony/symfony/issues/9887
| License       | MIT
| Doc PR        |

I propose to keep the `CacheInterface` and deprecate only the `ApcCache`.
It will leave the classes depending on a `CacheInterface` unchanged and will allow to adapt new cache providers in the future.

Commits
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3c4de45 [Validator] Added Doctrine cache