Pull Request: Fixes and Enhancements for ESP32 HTTPS Certificate Generation

[cturqueti]

The script 'create_cert.sh' had critical issues preventing reliable certificate generation:

1. CA validation errors (error 79)
2. Syntax errors from line endings
3. Non-standard certificate attributes

Changes Made:

1. CA Configuration Fixes

• Added proper X.509 v3 extensions for CA certificates
• Included critical CA constraints
• Set proper key identifiers

2. Certificate Signing Improvements

• Added required extensions for end-entity certificates
• Fixed subjectAltName generation
• Standardized key usage parameters

3. Cross-Platform Compatibility

• Normalized line endings (CRLF -> LF)
• Removed Windows-specific artifacts
• Added compatibility checks

4. Output File Generation

• Simplified header file creation
• Added error checking for xxd
• Improved file permission handling

Testing Performed:

• Windows (Git Bash)
• WSL/Ubuntu
• ESP32 Integration
• OpenSSL verification

Verification Command:
openssl verify -CAfile exampleca.crt example.crt

Impact:

• Enables reliable HTTPS server setup
• Works across development environments
• Maintains security standards

Notes for Reviewers:

• All changes backward compatible
• No dependency changes required
• Follows OpenSSL best practices