Remove studentify from sample projects

[seglo]

Short description

The examples currently use the studentify training aid to instruct users how to interatively develop any given example. This is good for training purposes, but it can make quick references from documentation difficult, especially since the studentify implementation is not explained to the user. I recommend reverting these examples to the standard SBT scala project directory structure and remove the studentify SBT code. We can tag the repo before this change if we want to explore providing Alpakka training examples some time in the future.