feat: support bitbucket self-hosted

[hywax]

🔗 Linked issue

resolves #188

• 📖 Documentation (updates to the documentation or readme)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

ENV: added GIGET_BITBUCKET_URL

❓ How to test

I found self-hosted in the public domain: https://bitbucket.hl7.org

1. Set env GIGET_BITBUCKET_URL=https://bitbucket.hl7.org
2. Run command pnpm run giget bitbucket:UTG/utg#master

Here's my successful log:

~/giget main ❯ pnpm run giget bitbucket:UTG/utg#master

> giget@1.2.3 giget /Users/Hywax/giget
> jiti ./src/cli.ts "bitbucket:UTG/utg#master"

✨ Successfully cloned UTG-utg to UTG-utg 

[hywax]

@pi0 would you please look at pr?