Move website source/build logic to projects/web

Mostly useful as it moves some of our build logic out of the main
project, as that's already pretty noisy!

projects/web/rollup.config.js

@@ -0,0 +1,58 @@
+import { readFileSync } from "fs";
+import path from "path";
+
+import typescript from "@rollup/plugin-typescript";
+import url from '@rollup/plugin-url';
+import { terser } from "rollup-plugin-terser";
+
+const input = "src";
+const requirejs = readFileSync("../../node_modules/requirejs/require.js");
+
+export default {
+    input: [`${input}/index.tsx`],
+    output: {
+        // Also defined in build.gradle.kts
+        dir: "build/rollup/",
+
+        // We bundle requirejs (and config) into the header. It's rather gross
+        // but also works reasonably well.
+        // Also suffix a ?v=${date} onto the end in the event we need to require a specific copy-cat version.
+        banner: `
+            ${requirejs}
+            require.config({
+                paths: { copycat: "https://copy-cat.squiddev.cc" },
+                urlArgs: function(id) { return id == "copycat/embed" ? "?v=20211221" : ""; }
+            });
+        `,
+        format: "amd",
+        preferConst: true,
+        amd: {
+            define: "require",
+        }
+    },
+    context: "window",
+    external: ["copycat/embed"],
+
+    plugins: [
+        typescript(),
+
+        url({
+            include: "**/*.dfpwm",
+            fileName: "[name]-[hash][extname]",
+            publicPath: "/",
+        }),
+
+        {
+            name: "cc-tweaked",
+            async transform(code, file) {
+                // Allow loading files in /mount.
+                const ext = path.extname(file);
+                return ext != '.dfpwm' && path.dirname(file) === path.resolve(`${input}/mount`)
+                    ? `export default ${JSON.stringify(code)};\n`
+                    : null;
+            },
+        },
+
+        terser(),
+    ],
+};