Make Reversible PPi Reactions Irreversible, Part 2

[Devlin-Moyer]

Main improvements in this PR:

As mentioned in the re-opening comment on #527:

• Makes MAR02786, MAR02802, MAR03388, MAR03390, and MAR09508 irreversible
• Swaps products and reactants of MAR01845, MAR09523, and MAR09546, then makes them irreversible

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

[edkerk]

I manually checked all changes, looks good to me.

[feiranl]

LGTM!