simplify post compile phase: shifting wire id is not needed 🙈

[gbotrel]

🙈 --> we used to do a weird dance in a post-compile phase, where we would loop through all constraints, logs, debuginfo, hints, and offset the ids of the wires. This was unnecessary complicated; new version just count the number of public and secret variables before calling Define, so, the r1cs builder and plonk builder both know the offset to add to new internal wires... voila.

• feat: remove post-compile offset id in R1CS builder
• feat: remove offset shifts in plonk compile

[ThomasPiellard]

Indeed it's simpler this way :) Is the Visibility field in Term still needed at all at this point? It was used when the public and secret variables were not a slice of []string, but a sort of wrapper around a variable...