Make pipelines less complex

We want to make building pipelines in Haystack easier and want to reduce the number of components in pipelines to make them concise and easier to read.
Examples:

• Add more super components so that users require fewer components for their pipelines
• Consider moving super components to a separate repo or to it's own folder
• Extend default (de-)serialization logic of custom components so that creating a custom component is less effort for users

No files, tests, or entry points are identified in the issue. Begin by surveying existing super components and the default custom-component serialization logic, then determine whether the work should reduce pipeline components, reorganize super components, or simplify serialization. Done means a concrete, agreed scope with tests or examples showing simpler pipelines or easier custom-component creation.