…-time serialization metadata (nicolas-grekas)

This PR was merged into the 7.4 branch.

Discussion
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[Serializer] Allow using attributes to declare compile-time serialization metadata

| Q             | A
| ------------- | ---
| Branch?       | 7.4
| Bug fix?      | no
| New feature?  | yes
| Deprecations? | yes
| Issues        | -
| License       | MIT

Very close to #61528
Prerequisite for #61287

At the moment, serialization attributes are read at runtime when `framework.serialization.enable_attributes` is true.

This means they don't fit for bundles nor can't they be warmed up.

This PR fixes both issues by using a new `serializer.attribute_metadata` resource tag, that's turned into a list of classes to parse for attributes at compile-time.

For bundles and for apps, the tag is added by explicit service configuration:
```php
        ->set('my_bundle.api_resource.product', Product::class)
            ->resourceTag('serializer.attribute_metadata')
```

Unlike validation where we have constraint attributes to auto-discover service resources, serialization doesn't have any corresponding hooks. We do have a few like `#[DiscriminatorMap]` of `#[Groups]`, but relying on those would miss many more classes that are meant for serialization. Maybe we could introduce an attribute that'd hint that some class is serializable by the component (and require the attribute at some point in the future?)

Commits
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bc6e054 [Serializer] Allow using attributes to declare compile-time serialization metadata