Change SourceManager implementation

[core23]

Subject

Fixes the build by changing the SourceManager implementation. The class has nothing to do with the exporter, so there is no need to implement the interface.

I am targeting this branch, because this is a breaking change.

Changelog

### Changed
- Change `SourceManager` implementation

[VincentLanglet]

Doc need to be updated too https://docs.sonata-project.org/projects/SonataSeoBundle/en/3.x/reference/sitemap/#service-definition

[VincentLanglet]

addTypes maybe ?

Or the addType should just add one type, and we should have the array_diff logic somewhere else.

Also the only usage of addSource is here:

SonataSeoBundle/src/DependencyInjection/SonataSeoExtension.php

Line 99 in f4ab958

$source->addMethodCall('addSource', [$sitemap['group'], new Reference($sitemapIteratorId), $sitemap['types']]);

Can't we know what is a type to give a more specific typehint than mixed ? (never used this bundle but I assume it's a string in https://docs.sonata-project.org/projects/SonataSeoBundle/en/3.x/reference/sitemap/#configuration-example)

Then having unique values are kinda easy with strings...

[core23]

addTypes maybe ?

Renamed the method.

Also the only usage of addSource is here:

SonataSeoBundle/src/DependencyInjection/SonataSeoExtension.php

Line 99 in f4ab958

$source->addMethodCall('addSource', [$sitemap['group'], new Reference($sitemapIteratorId), $sitemap['types']]);

That's not correct. The addSource method here calls the method on SourceIteratorInterface.

Can't we know what is a type to give a more specific typehint than mixed ? (never used this bundle but I assume it's a string in https://docs.sonata-project.org/projects/SonataSeoBundle/en/3.x/reference/sitemap/#configuration-example)

Never used this part either. For what I know, the type is just an array with an unknown signature. I would keep it as it is.

This PR started to just fix the broken 3.x build.

[core23]

Doc need to be updated too https://docs.sonata-project.org/projects/SonataSeoBundle/en/3.x/reference/sitemap/#service-definition

Why? Only the container for all SourceIteratorInterface was refactored.

The docs need to be updated when using the next exporter major version which will remove the SourceIteratorInterface.

[VincentLanglet]

Doc need to be updated too https://docs.sonata-project.org/projects/SonataSeoBundle/en/3.x/reference/sitemap/#service-definition

Why? Only the container for all SourceIteratorInterface was refactored.

The docs need to be updated when using the next exporter major version which will remove the SourceIteratorInterface.

My bad. I thought it wasnt needed to implement the interface and Iterator was only needed. Indeed it will only be changed in the next major.

[core23]

Please review @sonata-project/contributors so we can fix the broken 3.x branch. I would like to release a new major version soon.