Update Pulse Tutorial

[gebner]

The Pulse tutorial is slowly bitrotting away. We need to change that.

• The tutorial is not being updated nearly as much as it should since it's in a separate repository.
• The tutorial code is not being updated since that requires coordination with the other repo.
• The tutorial contains automatically generated code that is not being updated at all (and is out of date by now, as expected).
• Some examples in the tutorial are not checked at all and completely rotten away by now, as expected.

I propose the following changes in workflow:

1. We move the tutorial in the Pulse repo next to the accompanying code, to reduce coordination effort and widen the net of potential contributors.
2. Major PRs include updates to the tutorial.

Additionally, we need to do some one time work to get the tutorial up to date with the current state of the Pulse:

1. Examples need to be reviewed for current idiomatic style.
2. Recent additions to the language should be documented.
   • ANF
   • |-> syntax
   • preserves/multiple requires
   • new-style while loops
   • Impure specs
   • Gotos
   • Automatic lemmas
   • Located resources
   • Uninitialized memory