aiaprep can not be used to align AIA and HMI images

[Cadair]

aiaprep explicitly checks the type of the map to make sure it's AIAMap when really it should allow HMIMap as well because then you can align AIA images with HMI, and the metadata structure is sufficiently similar that there is no reason why this would not work.

The fix I think would be best would be to allow both AIAMap and HMIMap in this isinstance check. On the other hand you could just drop it altogether and just hope it works 😆

[wtbarnes]

Duplicate of #2331? Also see discussion in #1697.

[SolarDrew]

Well-spotted. I think having one function rescale both AIA and HMI data is a good solution to both this and #2331 if the plate scale is the only difference, but we'll have to put in a check so that it uses the correct one.

[Cadair]

if given a HMI map, aiaprep should change it's plate scale to 0.6. As that is how you would align it to the AIA data.

This is defiantly a dupe of #2331 though.