feat: add default front matter support

[benny123tw]

• Allow user to configure default front matter
• Wrap data.get('publish_date') with new Date to support JS Date Formats in the md file
• Set publish_date default to file's last modified date
• Convert tags to array to prevent TypeError tags?.map is not a function
• normalize the file path (this use to support windows file path) & decode the URI (support non-English words url)
• Update dependencies to std@0.151