refactor: replace nodegit with isomorphic-git

[kgajera]

Changes

• Refactors usages of nodegit to isomorphic-git
  • The only challenge was that there's no easy way to add all the untracked files. I followed their recommended approach: https://isomorphic-git.org/docs/en/faq#how-to-add-all-untracked-files-with-gitadd
• I noticed there were a few files being missed when copying from the template into a new bison project:
  • tsconfig.cjs.json - This wasn't being used anywhere but I've updated the yarn ts-node script to use it. This should also fix running this in Windows because it didn't like the format of passing the compiler options in as arguments.
  • .nvmrc
  • cypress/.eslintrc.json - this was not being copied because the cpy library excludes hidden files by default
• Removes packages/create-bison-app/yarn.lock. I don't think this file was being used anymore after switching to lerna.

Checklist

• [ ] Requires dependency update?
• [x] Generating a new app works

Fixes #149