Add AWS SAM CLI (#615)

Added in its own block because must be run as non-root user

Co-authored-by: Sergey Dolin <v-sedoli@micorosoft.com>

images/linux/scripts/installers/aws-sam-cli.sh

@@ -0,0 +1,24 @@
+#!/bin/bash
+################################################################################
+##  File:  aws-sam-cli.sh
+##  Desc:  Installs AWS SAM CLI
+##         Must be run as non-root user after homebrew and clang
+################################################################################
+
+# Source the helpers for use with the script
+source $HELPER_SCRIPTS/document.sh
+
+# Install aws sam cli
+brew tap aws/tap
+brew install aws-sam-cli
+
+# Run tests to determine that the software installed as expected
+echo "Testing to make sure that script performed as expected, and basic scenarios work"
+if ! sam --version; then
+    echo "AWS SAM CLI was not installed"
+    exit 1
+fi
+
+# Document what was added to the image
+echo "Lastly, documenting what we added to the metadata file"
+DocumentInstalledItem "AWS $(sam --version)"