Additional fields in ModeData structure

[wiredfool]

Changes proposed in this pull request:

• Additional hoisting of data from Storage.c into the const ModeData structure.
• Perf: Don't strcpy the band names and arrow format in for every new image.

Still considering --

• Should we leave the fields in the Image header? We can copy ints, we can copy addresses.
• Should we just have a pointer to the mode struct? This makes more changes across the code base.

[radarhere]

Should we just have a pointer to the mode struct? This makes more changes across the code base.

Could you clarify for me, what was the motivation behind the mode struct in the first place (#9256)? I thought it was primarily preparing the way for other field to be moved in there as well. Or was the theory that it would run strcmp less?