feat: Download platform tools in image (#202)

Every single verifiable build the process has to download platform
tools. This isn't coming on stdout and it is slow on dodgy wifi, it can
even timeout.
this introduces another pointless critical download opening to supply
chain attack.

Should this be backported to make new images since this does not change
the output?

Author: Arrowana

generate_dockerfiles.py

@@ -57,6 +57,11 @@
 RUN apt-get update && apt-get install -qy git gnutls-bin
 RUN sh -c "$(curl -sSfL https://release.anza.xyz/{AGAVE_VERSION_PLACEHOLDER}/install)"
 ENV PATH="/root/.local/share/solana/install/active_release/bin:$PATH"
+# Call cargo build-sbf to trigger installation of associated platform tools
+RUN cargo init temp && \\
+    cd temp && \\
+    cargo build-sbf && \\
+    rm -rf temp
 WORKDIR /build
 
 CMD /bin/bash