AIO_RUNTIME_NAMESPACE - where to find it?

Thanks jieyu

@navin_kumar0601 after you run `aio app init <name>`  using cli in the terminal, it will automatically generate a project firefly folder including all the init files, just follow the steps until completion. 

then get into the project folder, type `ls -a` to list out all the files, in the .env file, you will find hte AIO_RUNTIME_NAMESPACE