Improve rendering of WIP Cookiecutter Readmes

[aaronsteers]

In the wild, we're seeing a lot of taps and targets that still have "Developer TODO:" blocks in the public facing readme.

Let's clean these up so the developer todos are within markdown comments and not shown to readers and end-users.

So, by default, this creates a more concise README.md that is more readable and presentable to potential end users.