Add Http4s TodoMVC Example (500USD bounty)

[lihaoyi]

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From the maintainer Li Haoyi: I'm putting a 500USD bounty on this issue, payable by bank transfer on a merged PR implementing this.

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These should be example tests, similar to the exist one in example/scalalib/web/1-todo-webapp, but instead named example/scalalib/web/9-todo-http4s. It should have similar documentation/explanations, automated Usage test commands, and manual testing to verify the functionality works.

We should be able to reuse most of the existing frontend CsS and JS without changes. What is of interest is the server-side code and build configuration for the project

[c0d33ngr]

Working on this