Add project: A new plugin for displaying accurate document creation and last modification dates.

**Project details:** - Project Name: mkdocs-document-dates - Github URL: [mkdocs-document-dates](https://github.com/jaywhj/mkdocs-document-dates) - Category: 🌲 Git repos & info | 🤖 Code execution, variables & templating - License: MIT License - Package Managers: PyPI **Additional context:** A New MkDocs plugin for displaying **accurate** document creation and last modification dates, but no git dependency, uses filesystem timestamps directly, so see where this categorization fits in? **Features：** - Automatically displays document creation and last modification times - No Git dependency, uses filesystem timestamps directly - Supports manual date specification in `Front Matter` - Cross-platform support (Windows, macOS, Linux) - Configurable date and time formats - Flexible display position (top or bottom) - File exclusion rules support - Material Design icons - Elegant styling - Lightweight with no extra dependencies