[CI] add CI scripts separate from the workflows (#442)

_[One line description of your change]_

### Motivation:

_[Explain here the context, and why you're making that change. What is
the problem you're trying to solve.]_

### Modifications:

_[Describe the modifications you've done.]_

### Result:

_[After your change, what will change.]_

.github/workflows/scripts/check-archive-plugin.sh

@@ -0,0 +1,37 @@
+#!/bin/bash
+##===----------------------------------------------------------------------===##
+##
+## This source file is part of the SwiftAWSLambdaRuntime open source project
+##
+## Copyright (c) 2017-2024 Apple Inc. and the SwiftAWSLambdaRuntime project authors
+## Licensed under Apache License v2.0
+##
+## See LICENSE.txt for license information
+## See CONTRIBUTORS.txt for the list of SwiftAWSLambdaRuntime project authors
+##
+## SPDX-License-Identifier: Apache-2.0
+##
+##===----------------------------------------------------------------------===##
+
+EXAMPLE=HelloWorld
+OUTPUT_DIR=.build/plugins/AWSLambdaPackager/outputs/AWSLambdaPackager
+OUTPUT_FILE=${OUTPUT_DIR}/MyLambda/bootstrap
+ZIP_FILE=${OUTPUT_DIR}/MyLambda/MyLambda.zip
+
+pushd Examples/${EXAMPLE} || exit 1
+
+# package the example (docker and swift toolchain are installed on the GH runner)
+LAMBDA_USE_LOCAL_DEPS=../.. swift package archive --allow-network-connections docker || exit 1
+
+# did the plugin generated a Linux binary?
+[ -f "${OUTPUT_FILE}" ]
+file "${OUTPUT_FILE}" | grep --silent ELF
+
+# did the plugin created a ZIP file?
+[ -f "${ZIP_FILE}" ]
+
+# does the ZIP file contain the bootstrap?
+unzip -l "${ZIP_FILE}" | grep --silent bootstrap
+
+echo "✅ The archive plugin is OK"
+popd || exit 1

.github/workflows/scripts/check-link-foundation.sh

@@ -0,0 +1,52 @@
+#!/bin/bash
+##===----------------------------------------------------------------------===##
+##
+## This source file is part of the SwiftAWSLambdaRuntime open source project
+##
+## Copyright (c) 2017-2024 Apple Inc. and the SwiftAWSLambdaRuntime project authors
+## Licensed under Apache License v2.0
+##
+## See LICENSE.txt for license information
+## See CONTRIBUTORS.txt for the list of SwiftAWSLambdaRuntime project authors
+##
+## SPDX-License-Identifier: Apache-2.0
+##
+##===----------------------------------------------------------------------===##
+
+log() { printf -- "** %s\n" "$*" >&2; }
+error() { printf -- "** ERROR: %s\n" "$*" >&2; }
+fatal() { error "$@"; exit 1; }
+
+EXAMPLE=APIGateway
+OUTPUT_DIR=.build/release
+OUTPUT_FILE=${OUTPUT_DIR}/APIGatewayLambda
+LIBS_TO_CHECK="libFoundation.so libFoundationInternationalization.so lib_FoundationICU.so"
+
+pushd Examples/${EXAMPLE} || fatal "Failed to change directory to Examples/${EXAMPLE}."
+
+# recompile the example without the --static-swift-stdlib flag
+LAMBDA_USE_LOCAL_DEPS=../.. swift build -c release -Xlinker -s || fatal "Failed to build the example."
+
+# check if the binary exists
+if [ ! -f "${OUTPUT_FILE}" ]; then
+  error "❌ ${OUTPUT_FILE} does not exist."
+fi
+
+# Checking for Foundation or ICU dependencies
+echo "Checking for Foundation or ICU dependencies in ${OUTPUT_DIR}/${OUTPUT_FILE}."
+LIBRARIES=$(ldd ${OUTPUT_FILE} | awk '{print $1}')
+for LIB in ${LIBS_TO_CHECK}; do
+  echo -n "Checking for ${LIB}... "
+  
+  # check if the binary has a dependency on Foundation or ICU
+  echo "${LIBRARIES}" | grep "${LIB}"  # return 1 if not found
+
+  # 1 is success (grep failed to find the lib), 0 is failure (grep successly found the lib)
+  SUCCESS=$?
+  [ "$SUCCESS" -eq 0 ] && log "❌ ${LIB} found." && break || log "✅ ${LIB} not found."
+done
+
+popd || fatal "Failed to change directory back to the root directory."
+
+# exit code is the opposite of the grep exit code
+[ "$SUCCESS" -eq 0 ] && error "❌ At least one foundation lib was found, reporting the error." || log "✅ No foundation lib found, congrats!" && exit 0