Add asciinema shortcode and try in Playground

README.md

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+## Source of balki.me
+
+## Asciinema
+
+Followed instructions from here: https://jenciso.github.io/blog/embedding-asciinema-cast-in-your-hugo-site/
+
+Asciinema uses wasm which needs CSP unsafe-eval. Ref: https://www.aaron-powell.com/posts/2019-11-27-using-webassembly-with-csp-headers/