Upload checksums for installation artifacts (#4191)

The checksums are SHA-512 hashes, which users can use to verify file
integrity and authenticity.

scripts/dockerrun.sh

@@ -126,8 +126,11 @@ docker run $INTERACTIVE -t --rm --sig-proxy=true \
     -e NUGET_FEED_URL \
     -e NUGET_API_KEY \
     -e GITHUB_PASSWORD \
-    -e STORAGE_KEY \
-    -e STORAGE_ACCOUNT \
-    -e STORAGE_CONTAINER \
+    -e ARTIFACT_STORAGE_KEY \
+    -e ARTIFACT_STORAGE_ACCOUNT \
+    -e ARTIFACT_STORAGE_CONTAINER \
+    -e CHECKSUM_STORAGE_KEY \
+    -e CHECKSUM_STORAGE_ACCOUNT \
+    -e CHECKSUM_STORAGE_CONTAINER \
     $DOTNET_BUILD_CONTAINER_TAG \
     $BUILD_COMMAND "$@"