Add support for Symfony's DatePoint in DateHandler, close #1617

[Kocal]

Q	A
Bug fix?	no
New feature?	yes
Doc updated	no
BC breaks?	no
Deprecations?	no
Tests pass?	yes/no
Fixed tickets	#1617
License	MIT

[Kocal]

https://github.com/schmittjoh/serializer/actions/runs/21608912865/job/62381268400?pr=1618

Problem 1
- Root composer.json requires symfony/clock ^6.4 || ^7.0 || ^8.0 -> satisfiable by symfony/clock[v6.4.0, ..., v6.4.30, v7.0.0, ..., v7.4.0, v8.0.0].
- symfony/clock[v6.4.0, ..., v6.4.30] require php >=8.1 -> your php version (7.4.33) does not satisfy that requirement.
- symfony/clock[v7.0.0, ..., v7.4.0] require php >=8.2 -> your php version (7.4.33) does not satisfy that requirement.
- symfony/clock v8.0.0 requires php >=8.4 -> your php version (7.4.33) does not satisfy that requirement.

Hum, do you want me to remove symfony/clock from composer.json if PHP <8.1 in the CI, and mark tests as skipped if DatePoint is not available?

[scyzoryck]

Hum, do you want me to remove symfony/clock from composer.json if PHP <8.1 in the CI, and mark tests as skipped if DatePoint is not available?

Yes, please! Still there is about 8% of the users that are using PHP7.4 :(

[Kocal]

Should be better now :)