cargo/config: strip debuginfo from release bins

rustc -C strip=debuginfo leaves the symbol table intact, meaning
RUST_BACKTRACE=1 on the installer still produces helpful output.

This significantly reduces the binary size, eg the amd64 installer goes
from 93M to 21M. Stripping the symbol table only reclaims a further ~2M.

.cargo/config.toml

@@ -28,6 +28,7 @@ rustflags = ["-C", "target-feature=+crt-static"]
 # keep line numbers in stack traces for non-firmware binaries
 [profile.release]
 debug = "limited"
+strip = "debuginfo"
 
 # optimizations to reduce the binary size of firmware binaries
 [profile.firmware]
@@ -38,4 +39,3 @@ lto = true
 codegen-units = 1
 panic = "abort"
 debug = false
-