Add GitHub Login and Create PR Button for Committing Devcontainer

[nkkko]

Is your feature request related to a problem? Please describe.
Currently, users can generate devcontainer.json but have to manually commit it to the repository. Adding a GitHub login and an option to create a pull request (PR) directly from the interface will streamline the process.

Describe the solution you'd like

• Implement a GitHub login option to authenticate users.
• After successful login, display a "Create PR" button to commit the generated devcontainer.json directly to the repository.
• Ensure that the PR creation process:
  1. Forks the repository to the user's GitHub account.
  2. Commits the generated devcontainer.json to the forked repository.
  3. Creates a pull request from the fork to the original repository.

Describe alternatives you've considered

• Manually instructing users on how to copy and commit the devcontainer.json via GitHub interface.
• Using external GitHub CLI tools, which would complicate the workflow compared to an integrated solution.

Additional context

1. GitHub Login Integration:

   • Use OAuth to handle GitHub authentication.
   • Store user tokens securely for subsequent API calls.

2. Frontend Changes:

   • Add the "Create PR" button after successful login and devcontainer.json generation.

3. Backend Changes:

   • Update main.py to handle OAuth callback and store user token.
   • Implement a function to fork the repository, commit changes, and create a pull request using GitHub API.

Example Flow:

• User clicks "Login with GitHub".
• After authentication, the user generates the devcontainer.json.
• A "Create PR" button appears.
• Clicking the "Create PR" button forks the repo, commits the devcontainer.json, and creates a pull request.

Security Considerations:

• Ensure tokens are securely stored and managed.
• Handle user permissions carefully to avoid unauthorized changes.