- Remove the `prepare` script entirely
- Variables are now populated from the product.json during build. Most
variables are mapped automatically, with some special handling in a
few cases. `build.rs` is now much more self-contained.
- Look for the `product.overrides.json` for vscode developers instead of
looking for a peer `vscode-distro` folder
Fixes#178691
* build: don't apply cli 'patches' for merge check
This also needed modules installed. But with the new toml patches, the 'merge' will never fail outright, so there's no need to do a separate merge check for it imo
* reduce duplication in pipelines, cache node_modules
