This is still pretty quick and dirty, with lots of refactoring and
general tidying up ahead; but it gives an example structure to start
from

Emphasis on the dirty, not so much 'quick' ! This shows select outputs
from the default Asphodice class:
 - rerolls
 - outcome balance
 - outcomes

This information is presented in a Bootstrap card:

https://getbootstrap.com/docs/5.0/components/card/

In dev mode this means changes to ts files can now be watched
live.

Can now build all with 'gulp' (if gulp-cli installed)

Big commit. Breakdown:
 - .gitignore includes gulpfile.js (otehrwise excluded)
 - gulpfile sets up build steps + browsersync
 - src/ files for FE (stub for now)
 - moved ts to src/ for consistency
 - update tsconfig with new paths
 - package.json lists new reqs

Cancels out 10s and 1s, for use in rerollNeeded()

Aids unit testing which is needed for good practice and as we
are seeing bugs creep in around unnecessary rerolls

Also start sketching out results set for aggregate results