Split specs and content using separate YAML documents

What does this MR do and why?

Related to Define CI components syntax (#377327 - closed)

Related to Use YAML documents for CI templates' instead of... (#387038 - closed)

In this MR we change spec:inputs: and content: for a component to be 2 separate documents in the YAML. This way when we use with: inputs with other YAML files we can add inputs: in a header document while keeping the existing content as-is.

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