Images when STEREO COR was close to the Earth transit in 2023 need to be recalculated

[wafels]

This is because STEREO-A flipped when it passed Earth, causing problems for the existing backgrounds and data processing backgrounds.

Here is the latest information from STEREO.

Yes, we’re getting post-flip backgrounds again for COR2 and HI1. I also moved back the start date for using daily instead of monthly backgrounds. These periods are now

COR2: 2023-07-27 to 2023-08-18 inclusive
HI1: 2023-07-25 to 2023-08-30 inclusive

This is done by setting the keyword DAILY to true in the call to scc_getbkgimg.pro.