Make DownloaderDataProvider take an array

[Martin-Molinero]

Expected Behavior

Actual Behavior

• Currently DownloaderDataProvider can take a single downloader instance. This class is used by the lean cli when passing data providers to use

Potential Solution

• Ideally DownloaderDataProvider can take an array of downloader instances to use, like we do with IDQH and history providers, so that we can merge multiple different data provider sources. Once implemented in lean, lean cli needs to be updated to provide them

Reproducing the Problem

N/A

System Information

N/A

Checklist

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