Remove fomantic input module (#30194)

Another pure CSS module. Some styling is part of the `form` module which
will likely follow next.

web_src/css/index.css

@@ -6,6 +6,7 @@
 @import "./modules/container.css";
 @import "./modules/divider.css";
 @import "./modules/header.css";
+@import "./modules/input.css";
 @import "./modules/label.css";
 @import "./modules/segment.css";
 @import "./modules/grid.css";