soupault: add page (#8559)

* soupault: add page

* Update pages/common/soupault.md

pages/common/soupault.md

@@ -0,0 +1,25 @@
+# soupault
+
+> Soupault is a static website generator based on HTML element tree rewriting.
+> It can also be used as an HTML post-processor or metadata extractor.
+> More information: <https://soupault.app>.
+
+- Initialize a minimal website project in the current working directory:
+
+`soupault --init`
+
+- Build a website:
+
+`soupault`
+
+- Override default config file and directory locations:
+
+`soupault --config {{config_path}} --site-dir {{input_dir}} --build-dir {{output_dir}}`
+
+- Extract metadata into a JSON file without generating pages:
+
+`soupault --index-only --dump-index-json {{path/to/file.json}}`
+
+- Show the effective config (values from `soupault.toml` plus defaults):
+
+`soupault --show-effective-config`