28 enh add optional GitHub integrations to flow

[JordanJunaidi]

Summary

Implements GitHub integrations to project scaffolding flow. The user now has the option to initialize a GitHub repository and push the initial commit.

Closes #28

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Changes Made

• Added new stack: <stack name>
• Updated existing functionality
• Improved documentation
• Refactored internal code
• Fixed a bug

Briefly summarize the major changes:

• Repaired previously existing GitHub integration flow
• Added UseGitHub flag to make GitHub integration optional
• Split InitAndPush function into 3 helpers functions (Init, Commit, Push)

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Testing

How was this change tested?

• go test ./... passes locally
• Manual testing done with taco CLI
• CI checks pass

Provide details:

# Example test commands
./taco init

Note: GITHUB_TOKEN must be a classic token with repo create and delete permissions