project manager respond to README

[johrstrom]

The idea for this ticket is fairly straight forward. If the project has a README.txt or README.md in the root of the project, we should display that.

The motivation being something like this: The project (template most likely) is for a semester or perhaps a joint research study. In any case, the README has information about what to do, how to do it and so on.

The UI for the project manager is in flux, so I'm not sure where we could display it on the projects#show page, but that can be sorted out as we go.

[ashton22305]

Fixed in #3678