serve FITS images via the Blast API

[djones1040]

🚀 Feature Request

Is your feature request related to a problem? Please describe.

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Describe the solution you'd like

• It would be convenient to be able to download the stored FITS cutouts of the transient location and host galaxy via the Blast API. As it currently stands, we have to get fits images from the individual survey APIs rather than through Blast.

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Describe alternatives you've considered

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Additional context