Astrometry last cleanup

This ticket is designed to bring together the latest cleaning work to be done in astrometry.

• fixes #1403 (closed)
• check low height/width ratio
• check limit mag during nearsearch
• check this: https://www.webastro.net/forums/topic/257080-param%C3%A9trage-par-d%C3%A9faut-de-la-fonction-astrom%C3%A9trie-sur-une-s%C3%A9quence/#comment-3171907
• create new sequence for fitseq as well (use writer)
• review limits in check_affine_TRANS_sanity
• check consistency of interpolate non-green pixels for single image/sequence with/without platesolve (clear fit stats)
• move lst files to .cache/ folder
• make sure master file is saved in .seq in case it's later changed or cleared