Deprecating using the WebspaceManger for getting webspaces

[mamazu]

Q	A
Bug fix?	no
New feature?	no
BC breaks?	no
Deprecations?	yes
Fixed tickets	-
Related issues/PRs	#7218
License	MIT
Documentation PR	-

What's in this PR?

• Making the WebspaceCollection it's own service.
• Deprecating repository like functions on the WebspaceManager
• Adding constructor arguments to Webspace objects.

Why?

We want to split those huge services up. That way we reduce the amount of dependencies a class has.

Example Usage

OLD:

class SomeClass {
    public function __construct(
        private WebspaceManager $webspaceManager
    ) {}

    public function doSomething(): ?string 
    {
        return $this->webspaceManager->findWebspaceByKey('someKey')?->getName();
    }
}

NEW:

class SomeClass {
    public function __construct(
        private WebspaceCollection $webspaceCollection
    ) {}

    public function doSomething(): ?string 
    {
        return $this->webspaceCollection->getWebspace('someKey')?->getName();
    }
}

To Do

• Create a documentation PR
• Add breaking changes to UPGRADE.md

[mamazu]

Technically passing null to those parameters will be also removed in 3.0.

[mamazu]

@alexander-schranz Can you have a look at this and merge if possible?