Add append-path to build terminals' PATH
In a project where the active Flatpak manifest has for example
"build-options" : {
"append-path" : "/usr/lib/sdk/rust-stable/bin",
"prepend-path": "/usr/lib/sdk/llvm12/bin",
}
it could be desirable to have those paths automatically added/prepended to the PATH
when opening a Build Terminal.
This comes up very often in rust development, where you need to extend the PATH before running meson dist
every time you want to vendor dependencies for a release, or when you want to call different Rust linters/formaters from Builder's cli.