chore: move Gulp tasks for SCSS transpile, moving assets to esbuild

I think migrating to esbuild over time *could* help mitigate some
issues, the most notable one being the weird requirement for a network
connection to build PrivacySpy (which is ridiculous in general).

deps:

gulpfile.ts

@@ -14,7 +14,6 @@ import {
 } from "./src/build/utils";
 
 const gulp = require("gulp");
-const postcss = require("gulp-postcss");
 const fs = require("node:fs");
 const path = require("node:path");
 const through = require("through2");
@@ -95,57 +94,11 @@ gulp.task(
   )
 );
 
-gulp.task("collect dependencies", () => {
-  return gulp
-    .src(["./node_modules/lunr/lunr.min.js"])
-    .pipe(gulp.dest("./dist/static/deps/"));
-});
-
-gulp.task("collect static", () => {
-  return gulp
-    .src([
-      "./src/static/**/*",
-      "./node_modules/@fortawesome/fontawesome-free/**/*.{woff2,woff}",
-      "!./src/static/**/*.{css,scss}",
-    ])
-    .pipe(gulp.dest("./dist/static/"));
-});
-
-gulp.task("collect root favicon", () => {
-  return gulp.src(["./src/static/img/*.ico"]).pipe(gulp.dest("./dist/"));
-});
-
-gulp.task("collect product icons", () => {
-  return gulp.src(["./icons/**/*"]).pipe(gulp.dest("./dist/static/icons/"));
-});
-
-gulp.task("build css", () => {
-  return gulp
-    .src(["./src/static/css/base.scss"])
-    .pipe(postcss())
-    .pipe(through.obj((file, _, cb) => { // change to .css extension
-      if (file.isBuffer()) {
-        const fp = path.format({
-          dir: path.dirname(file.path),
-          name: path.basename(file.path, ".scss"),
-          ext: '.css'
-        })
-      }
-      cb(null, file);
-    }))
-    .pipe(gulp.dest("./dist/static/css/"));
-});
-
 gulp.task(
   "default",
   gulp.series([
     "clean",
     "build pages",
-    "collect dependencies",
-    "collect static",
-    "collect product icons",
-    "collect root favicon",
-    "build css",
   ])
 );