refactor(conf): migrate to toml

src/sphinx_theme_ref/theme.toml

@@ -0,0 +1,24 @@
+[theme]
+inherit = "basic"
+stylesheets = [
+    "style/main.css",
+]
+sidebars = [
+    "localtoc.html",
+    "relations.html",
+    "sourcelink.html",
+    "searchbox.html",
+]
+# Style names from https://pygments.org/styles/
+pygments_style = { default = "style_name", dark = "dark_style" }
+
+[options]
+nosidebar = false
+sidebarwidth = 230
+body_min_width = 360
+body_max_width = 800
+navigation_with_keys = False
+enable_search_shortcuts = True
+globaltoc_collapse = true
+globaltoc_includehidden = false
+globaltoc_maxdepth =