Public File Sharing (#72)

* Public File Sharing

This implements public file sharing (read-only) with and without passwords (#57).

It also fixes a problem with filenames including special characters like `#` not working properly (#71).

You can share a directory or a single file, by using the new share icon on the right of the directories/files, and click on it to manage an existing file share (setting a new password, or deleting the file share).

There is some other minor cleanup and other copy updates in the README.

Closes #57
Fixes #71

* Hide UI elements when sharing isn't allowed

deno.json

@@ -10,7 +10,14 @@
     "update": "deno run -A -r https://fresh.deno.dev/update .",
     "test": "deno test -A --check"
   },
-  "fmt": { "useTabs": false, "lineWidth": 120, "indentWidth": 2, "singleQuote": true, "proseWrap": "preserve" },
+  "fmt": {
+    "useTabs": false,
+    "lineWidth": 120,
+    "indentWidth": 2,
+    "singleQuote": true,
+    "proseWrap": "preserve",
+    "exclude": ["README.md"]
+  },
   "lint": {
     "rules": {
       "tags": ["fresh", "recommended"],