Remove Tagatose-1,6-Bisphosphate

[Devlin-Moyer]

Main improvements in this PR:

As proposed in #754:

• Removes MAR04774, MAR04775, and MAR02955c because they don't seem to occur in human cells
• Updates references for other reactions involving tagatose that previously had no references or references that did not directly support their existence in humans (MAR09417, MAR08760, MAR01472, MAR01038, MAR08761, and MAR08762)

I hereby confirm that I have:

• Tested my code on my own computer for running the model
• Selected develop as a target branch
• Any removed reactions and metabolites have been moved to the corresponding deprecated identifier lists

[JHL-452b]

It looks fine to me, and the implementation matchs with the claims in PR message.

[feiranl]

LGTM!