Build avar1 TTFs

[davelab6]

Similar to https://github.com/googlefonts/roboto-delta/blob/main/Source/build-RobotoDelta-statics.sh I'd like to request making a few avar1 builds:

1. only user axes (weight, width, optical size, grade)
2. only user + primary parametric axes (weight, width, optical size, grade + xopq, yopq, xtra, xtsp, ytlc)
3. all axes, same as the avar2 build

I have a team within Google interested in using Amstelvar, but they need to ship it in non-avar2-capable environments, and probably only use (1) but may use (2), and (3) would be good to have just in case :)