Improve workflow.bonsai double-click experience

[PathogenDavid]

(As discussed here: #1956 (comment))

Right now double-clicking a Bonsai workflow from Windows Explorer always opens the system Bonsai by default. For those using repo-local Bonsai environments, it should open that Bonsai instead.

An immediate solution could be to have the bootstrapper recognize when a repo-local Bonsai environment folder exists and launch Bonsai from there.

This is also something I've been planning to address with my not-so-secret Bonsai environments/bootstrapping revamp proposal (where the solution will not be the same.)