add powershell and bash scripts for replacing default webassembly nuget packages from link or path (#19498)

sdks/wasm/package-update/download-packages.ps1

@@ -0,0 +1,26 @@
+param ($filepath, $url, $runtime)
+$PACKAGE_PATH="~\\.nuget\\packages\\microsoft.aspnetcore.components.webassembly.runtime\\$runtime\\tools\\dotnetwasm"
+
+if ($null -eq $filepath) {
+	Invoke-WebRequest -Uri $url -OutFile wasm-package.zip -UseBasicParsing
+
+	Expand-Archive wasm-package.zip 
+	cd wasm-package
+}
+else {
+	cd $filepath
+}
+
+rm -r $PACKAGE_PATH\bcl
+cp wasm-bcl $PACKAGE_PATH\bcl
+
+rm -r $PACKAGE_PATH\framework
+cp framework $PACKAGE_PATH\framework
+
+rm -r $PACKAGE_PATH\wasm\*
+cp builds\release\dotnet.$runtime.js $PACKAGE_PATH\wasm\
+cp builds\release\dotnet.wasm $PACKAGE_PATH\wasm\
+
+cd ..
+rm wasm-package.zip
+rm -r wasm-package

sdks/wasm/package-update/download-packages.sh

@@ -0,0 +1,45 @@
+#!/bin/bash
+while (("$#"));
+do 
+    key="${1}"
+    
+    case ${key} in
+    -r|--runtime)
+        RUNTIME="$2"
+        shift 2
+        ;;
+    -f|--filepath)
+        FILEPATH="$2"
+        shift 2
+        ;;
+    -u|--url)
+        URL="$2"
+        shift 2
+        ;;
+    *)
+        shift
+        ;;
+    esac
+done
+
+PACKAGE_PATH=$HOME/.nuget/packages/microsoft.aspnetcore.components.webassembly.runtime/$RUNTIME/tools/dotnetwasm
+
+if [ -z "$FILEPATH" ]
+then
+    wget -O wasm-package.zip $URL
+    unzip wasm-package.zip -d wasm-package/
+    FILEPATH=wasm-package/
+fi
+
+rm -r $PACKAGE_PATH/bcl
+cp $FILEPATH/wasm-bcl $PACKAGE_PATH/bcl
+
+rm -r $PACKAGE_PATH/framework
+cp $FILEPATH/framework $PACKAGE_PATH/framework
+
+rm "$PACKAGE_PATH"/wasm/*
+cp $FILEPATH/builds/release/dotnet.$RUNTIME.js $PACKAGE_PATH/wasm/
+cp $FILEPATH/builds/release/dotnet.wasm $PACKAGE_PATH/wasm/
+
+rm wasm-package.zip
+rm -rf wasm-package