Modernize 2025 (#520)

This comprehensive update modernizes the Missing Maps website with improved security, performance, and maintainability.

## Major Changes

### Infrastructure Modernization
- **Node.js**: Upgraded from 12.16.1 (EOL) to 20.18.0 LTS
- **Ruby**: Updated to 3.3.5 with Jekyll 4.3.4
- **CI/CD**: Migrated from Travis CI to GitHub Actions with automated testing
- **Dependencies**: Fixed 40+ security vulnerabilities, updated all packages

### Internationalization Overhaul
- **Jekyll Polyglot**: Replaced manual language system with modern plugin
- **Code Reduction**: Eliminated 65+ duplicate files, now 13 centralized templates
- **Automatic generation**: Language directories created automatically
- **Maintained compatibility**: All URLs and translations preserved

### Build System Improvements
- **Modern JavaScript**: Converted to ES6+, updated ESLint configuration
- **Gulp 5**: Updated build pipeline with dart-sass and modern dependencies
- **GitHub Actions**: Comprehensive CI/CD with security scanning and automated deployments
- **Performance**: Added incremental builds, SASS compression, parallel localization

### Content & Security Updates
- **HTTPS enforcement**: Fixed mixed content issues
- **OSMCal integration**: Modernized event management
- **HOT Field Tasking Manager**: Replaced deprecated POSM references
- **Asset updates**: Added new graphics and documentation

### Developer Experience
- **Documentation**: Added comprehensive guides (INTERNATIONALIZATION.md, QUICK-REFERENCE.md)
- **Testing**: Automated multilingual functionality tests
- **Modern tooling**: Updated all development dependencies and workflows

## Benefits
- ✅ Zero security vulnerabilities
- ✅ Modern, maintainable codebase
- ✅ Faster builds and deployments
- ✅ Simplified language management
- ✅ Comprehensive testing and documentation
- ✅ Future-proof architecture

Author: dalekunce

.build_scripts/deploy.sh

@@ -0,0 +1,78 @@
+name: Bug Report
+description: Report a bug or issue with the Missing Maps website
+title: "[Bug]: "
+labels: ["bug", "needs-triage"]
+assignees: []
+
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for taking the time to report a bug! Please fill out the form below to help us understand and reproduce the issue.
+
+  - type: input
+    id: url
+    attributes:
+      label: Page URL
+      description: What page were you on when you encountered the bug?
+      placeholder: https://www.missingmaps.org/...
+    validations:
+      required: false
+
+  - type: textarea
+    id: description
+    attributes:
+      label: Bug Description
+      description: A clear and concise description of what the bug is
+      placeholder: Describe what happened and what you expected to happen
+    validations:
+      required: true
+
+  - type: textarea
+    id: steps
+    attributes:
+      label: Steps to Reproduce
+      description: How can we reproduce this bug?
+      placeholder: |
+        1. Go to...
+        2. Click on...
+        3. Scroll down to...
+        4. See error
+    validations:
+      required: true
+
+  - type: dropdown
+    id: browsers
+    attributes:
+      label: Browser
+      description: What browser are you using?
+      options:
+        - Chrome
+        - Firefox
+        - Safari
+        - Edge
+        - Mobile Safari
+        - Mobile Chrome
+        - Other
+    validations:
+      required: false
+
+  - type: dropdown
+    id: device
+    attributes:
+      label: Device Type
+      description: What type of device are you using?
+      options:
+        - Desktop
+        - Mobile
+        - Tablet
+    validations:
+      required: false
+
+  - type: textarea
+    id: additional
+    attributes:
+      label: Additional Context
+      description: Add any other context about the problem here, including screenshots if helpful
+    validations:
+      required: false

.build_scripts/lint.sh

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+# GitHub Actions Workflows
+
+This directory contains the CI/CD workflows for the Missing Maps website.
+
+## Workflows
+
+### 📦 `deploy.yml` - CI/CD Pipeline
+- **Triggers**: Push to `main`, `master`, or `publish` branches; Pull requests
+- **Purpose**: Build and deploy the site to GitHub Pages
+- **Features**:
+  - Ruby and Node.js environment setup
+  - Dependency caching
+  - JavaScript linting
+  - Jekyll build with Gulp
+  - Automated deployment to GitHub Pages (publish branch only)
+
+### 🧪 `test.yml` - Pull Request Tests
+- **Triggers**: Pull requests to main branches
+- **Purpose**: Test builds and validate changes
+- **Features**:
+  - Build verification
+  - Asset generation checks
+  - Lint validation
+
+### 🔒 `security.yml` - Security and Dependency Checks
+- **Triggers**: Weekly schedule, dependency file changes, manual trigger
+- **Purpose**: Monitor security and dependency health
+- **Features**:
+  - NPM security audit
+  - Ruby security audit with bundler-audit
+  - Outdated dependency checks
+  - Code linting and formatting validation
+
+## Dependabot Configuration
+
+The `.github/dependabot.yml` file configures automated dependency updates:
+- **NPM packages**: Weekly updates on Sundays
+- **Ruby gems**: Weekly updates on Sundays  
+- **GitHub Actions**: Weekly updates on Sundays
+- **Grouping**: Development vs production dependencies
+- **Auto-assignment**: PRs assigned to maintainers
+
+## Migration from Travis CI
+
+This setup replaces the previous Travis CI configuration with modern GitHub Actions:
+- ✅ Improved security with GitHub's built-in secrets management
+- ✅ Better integration with GitHub features
+- ✅ More granular control over workflows
+- ✅ Built-in GitHub Pages deployment
+- ✅ Automated dependency management
+
+## Required Secrets
+
+No additional secrets are required - GitHub Actions uses built-in `GITHUB_TOKEN` for deployment.
+
+## Branch Strategy
+
+- **`publish`**: Production deployment branch (auto-deploys to GitHub Pages)
+- **`main`/`master`**: Development branch (tests only)
+- **Feature branches**: Pull request testing only