DocumentWriter (v2)

[ZanSara]

Blocked by #5261

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DocumentWriter is a tiny, document-store-agnostic component that simply takes one list of documents and writes it to the document store.

Example of such component:

@component
class WriteToStore(StoreAwareMixin):

    @component.input
    def input(self):
        class Input:
            documents: List[Document]
        return Input

    @component.output
    def output(self):
        class Output:
             ...
        return Output

    def run(self, data):
        self.store.write_documents(data.documents)
        return self.output()