use internal bun drv and bun 1.0.1

[cdmistman]

Why

been getting a lot of bumps about updating bun package for replit, but relying on upstream nixpkgs for this means we actually lose 2 workdays (not including weekends) every time there's a release before we're caught up on bun versions

we'll just internally maintain a duplicate version of the bun derivation from upstream, but once the hype dies down we'll want to remove it and rely on upstream

What changed

• brought the bun derivation file into this repo
• use the internal derivation for bun module
• update bun to 1.0.1

Test plan

• install bun-1.0 module v2
• bun --version prints 1.0.1

Rollout

Describe any procedures or requirements needed to roll this out safely (or check the box below)

• This is fully backward and forward compatible