Add Uriel static site generator (#840)

* Add Uriel static site generator

* Remove wayward '.' in bullet point items for Uriel static site generator

Author: ratherlargerobot

src/site/generators/uriel.md

@@ -0,0 +1,42 @@
+---
+title: Uriel
+repo: ratherlargerobot/uriel
+homepage: https://nathanrosenquist.com/uriel/
+language:
+  - Python
+license:
+  - GPL-3.0-or-later
+templates:
+  - Custom
+description: Minimalistic, stable, feature complete static site generator.
+---
+
+Uriel is a minimalistic, stable, feature complete static site generator,
+written in Python.
+
+Built to last for years without requiring any maintenance. It is feature
+complete, and only depends on python3 and rsync, with no third-party module
+dependencies. That means that it won't break unexpectedly years from now,
+after you've built a site around it.
+
+As long as you can still get a working copy of python3 and rsync, your site
+will still build the same way in the future.
+
+### Features
+
+- Extensible template system
+- Built-in substitution parameter support in content nodes and templates
+- Write arbitrary Python code, and call it from content nodes and templates
+- Write arbitrary Python code, and have it generate pages dynamically
+- Possible to build a basic site without writing any Python code
+- Flat URL support to make some or all content nodes top-level URLs
+- Static file linking lets you catch potential 404 errors at build time
+- Static file hash linking support for dynamically generated CSS/JavaScript file includes
+- Content node metadata inheritance system
+- Built-in tag index system
+- RSS feed support
+- sitemap.xml support
+- Creates basic robots.txt file
+- Useful error messages
+- Stable, feature complete platform
+- Almost entirely self-contained, only depends on python3 and rsync