feat: Add GitHub workflows for issue and PR automation (#138)

[vansh-09]

Description

This pull request introduces a comprehensive set of GitHub Actions workflows to automate and streamline issue and pull request management for the repository. The new workflows handle issue assignment, labeling, PR reviewer assignment, difficulty classification, and label inheritance, all tailored to support contribution programs like GSSoC. These automations aim to reduce manual overhead, ensure consistency, and improve the contributor experience.

**Fixes #138 **

Changes Made

Automated Issue and PR Management Workflows:

Auto-assignment and Labeling:

• Added .github/ISSUE_TEMPLATE/workflows/auto-assign.yml to automatically assign issues to commenters who express intent to work on them using trigger phrases, with logic to handle already-assigned issues and provide user feedback.
• Introduced .github/ISSUE_TEMPLATE/workflows/pr-auto-assign.yml to automatically assign new pull requests to their authors, apply a gssoc:approved label, and post a welcome comment with contribution tips.

Automated Labeling and Classification:

• Added .github/ISSUE_TEMPLATE/workflows/issue-triage.yml to auto-label new issues based on their content (e.g., bug, feature, docs, design, etc.) and always tag them with the gssoc label.
• Implemented .github/ISSUE_TEMPLATE/workflows/difficulty.yml to analyze pull requests and assign a difficulty label (level:beginner, level:intermediate, level:advanced, level:critical) based on the number of files/lines changed and whether core files are affected.

Reviewer Assignment and PR Handling:

• Added .github/ISSUE_TEMPLATE/workflows/pr-reviewer.yml to automatically assign the repository owner as a reviewer for new or ready-for-review pull requests, except when the owner is the author.

Label Inheritance and Special Cases:

• Introduced .github/ISSUE_TEMPLATE/workflows/pr-label-inheritence.yml to inherit non-managed labels from linked issues to pull requests (excluding labels managed by other workflows), and to add a hacktoberfest-accepted label for PRs opened in October.

Screenshots (if applicable)

N/A

Checklist

• I have linked the relevant issue above.
• I have tested my changes locally.
• My code follows the project's style guidelines.

[vercel]

@vansh-09 is attempting to deploy a commit to the Mayo's projects Team on Vercel.

A member of the Team first needs to authorize it.

[vansh-09]

@mayo-byte07 please review

[Akshita-2307]

Hi! I'd like to work on this issue. Could you please assign it to me? I'll make sure to follow the project's guidelines and maintain high code quality. Thanks!