Make gradle go fast

[solonovamax]

Changes:

• Use gradle convention plugins instead of allprojects and subprojects
• Move version catalog to libs.versions.toml
• Add funny gradle.properties settings to make gradle go fast
• Default to project properties first for secrets, but fail over to env variables
• Use version catalog bundles

LMK if this works.

I got the gradle build times down from "had an OOM and then just hung and never finished" to like 30 seconds (assuming that deps don't need to be remapped. That takes longer) (tested by deleting all build dirs then running gradle build)

[sisby-folk]

merging this now so I can tinker with it - please let us know if you'd like to be credited under any other name!