…` parameters to `IpUtils::anonymize()` (alexandre-daubois)

This PR was merged into the 7.2 branch.

Discussion
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[HttpFoundation] Add optional `$v4Bytes` and `$v6Bytes` parameters to `IpUtils::anonymize()`

| Q             | A
| ------------- | ---
| Branch?       | 7.2
| Bug fix?      | on
| New feature?  | yes
| Deprecations? | no
| Issues        | Fix #50778
| License       | MIT
| Doc PR | symfony/symfony-docs#20138

This PR answers to the need of more anonymization of IP addresses. This adds 2 new parameters to the `IpUtils::anonymize()` that you can use this way:

```php
$ipv4 = '123.234.235.236';
$anonymousIpv4 = IpUtils::anonymize($ipv4, v4Bytes: 3);
// $anonymousIpv4 = '123.0.0.0'

$ipv6 = '2a01:198:603:10:396e:4789:8e99:890f';
$anonymousIpv6 = IpUtils::anonymize($ipv6, v6Bytes: 10);
// $anonymousIpv6 = '2a01:198:603::'
```

Commits
-------

53c4f92 [HttpFoundation] Add optional `$v4Bytes` and `$v6Bytes` parameters to `IpUtils::anonymize()`