✨(sdk) add sdk projects

It includes a consumer project which is simply a demo app. The sdk
project includes the first version of the SDK, with a light React
implementation. The first version lays down the foundations of
the iframe sdk framework. The npm package logic is also already
ready to be published.

src/sdk/consumer/.gitignore

@@ -0,0 +1,24 @@
+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+pnpm-debug.log*
+lerna-debug.log*
+
+node_modules
+dist
+dist-ssr
+*.local
+
+# Editor directories and files
+.vscode/*
+!.vscode/extensions.json
+.idea
+.DS_Store
+*.suo
+*.ntvs*
+*.njsproj
+*.sln
+*.sw?