More efficient flat file list format and various UX improvements (#3)

This is a major upgrade with assorted things included.

- Navigation flows improved, search appears in URL history, cleared when navigating to another folder
- More efficient file list format for faster loads
- Efficient updates, never re-send full root another time (except at connection)
- Large number of watching and filelist updates (inotify issues remain)
- File size coloring
- Fixed ZIP generation random glitches (thread race condition)
- Code refactoring, cleanup, typing fixes
- More tests

frontend/src/router/index.ts

@@ -0,0 +1,15 @@
+import { createRouter, createWebHashHistory } from 'vue-router'
+import ExplorerView from '@/views/ExplorerView.vue'
+
+const router = createRouter({
+  history: createWebHashHistory(import.meta.env.BASE_URL),
+  routes: [
+    {
+      path: '/:pathMatch(.*)*',
+      name: 'explorer',
+      component: ExplorerView
+    }
+  ]
+})
+
+export default router