Wrong fonts content-type when UiPassword is enabled

### Step 1: Please describe your environment

* ZeroNet version: **0.7.0 r4059**
* Operating system: **Arch Linux**
* Web browser: **Firefox 66**
* Tor status: **enabled**
* Opened port: **yes**
* Special configuration:

### Step 2: Describe the problem:
When UiPassword is enabled, some files, fonts are sent with `Content-Type: text/html; charset=utf-8`, getContentType doesn't get called on them. Also `Access-Control-Allow-Origin` header is missing.
#### Steps to reproduce:

1. Open site `http://127.0.0.1:43110/14c5LUN73J7KKMznp9LvZWkxpZFWgE1sDz/` with UiPassword disabled.
2. Content-type of `http://127.0.0.1:43110/14c5LUN73J7KKMznp9LvZWkxpZFWgE1sDz/fonts/material-icons/MaterialIcons-Regular.woff2` is `application/octet-stream`.
3. Enable UiPassword and reload site.
4. Content-type of `http://127.0.0.1:43110/14c5LUN73J7KKMznp9LvZWkxpZFWgE1sDz/fonts/material-icons/MaterialIcons-Regular.woff2` is `text/html; charset=utf-8` and browser blocks request because `Access-Control-Allow-Origin` header is missing.

#### Observed Results:

Fonts fail to load because of wrong content-type and missing `Access-Control-Allow-Origin` header.
I added `print('getContentType called: file_name={}, content_type={}'.format(file_name, content_type))` to getContentType and this is what I got:
UiPassword disabled:

> getContentType called: file_name=index.html, content_type=text/html
> getContentType called: file_name=all.css, content_type=text/css
> getContentType called: file_name=all.css, content_type=text/css
> getContentType called: file_name=all.js, content_type=application/javascript
> getContentType called: file_name=logo-white.png, content_type=image/png
> getContentType called: file_name=index.html, content_type=text/html
> getContentType called: file_name=fonts/material-icons/material-icons.css, content_type=text/css
> getContentType called: file_name=material-icons.css, content_type=text/css
> getContentType called: file_name=css/main.css, content_type=text/css
> getContentType called: file_name=main.css, content_type=text/css
> getContentType called: file_name=css/asciinema-player.css, content_type=text/css
> getContentType called: file_name=asciinema-player.css, content_type=text/css
> getContentType called: file_name=js/asciinema-player.js, content_type=application/javascript
> getContentType called: file_name=asciinema-player.js, content_type=application/javascript
> getContentType called: file_name=js/all.js, content_type=application/javascript
> getContentType called: file_name=all.js, content_type=application/javascript
> **getContentType called: file_name=fonts/material-icons/materialicons-regular.woff2, content_type=application/octet-stream**
> **getContentType called: file_name=materialicons-regular.woff2, content_type=application/octet-stream**

UiPassword enabled:

> getContentType called: file_name=index.html, content_type=text/html
> getContentType called: file_name=all.css, content_type=text/css
> getContentType called: file_name=all.css, content_type=text/css
> getContentType called: file_name=all.js, content_type=application/javascript
> getContentType called: file_name=logo-white.png, content_type=image/png
> getContentType called: file_name=index.html, content_type=text/html
> getContentType called: file_name=css/main.css, content_type=text/css
> getContentType called: file_name=main.css, content_type=text/css
> getContentType called: file_name=fonts/material-icons/material-icons.css, content_type=text/css
> getContentType called: file_name=material-icons.css, content_type=text/css
> getContentType called: file_name=css/asciinema-player.css, content_type=text/css
> getContentType called: file_name=asciinema-player.css, content_type=text/css
> getContentType called: file_name=js/asciinema-player.js, content_type=application/javascript
> getContentType called: file_name=asciinema-player.js, content_type=application/javascript
> getContentType called: file_name=js/all.js, content_type=application/javascript
> getContentType called: file_name=all.js, content_type=application/javascript

#### Expected Results:

Zeronet sends fonts with right headers and browser loads them.

未指定文件或测试。分别在禁用和启用 UiPassword 的情况下，复现对 MaterialIcons-Regular.woff2 URL 的请求，然后跟踪 getContentType 路径和 UiPassword 响应处理。两种情况下字体都收到正确的 content type 和 Access-Control-Allow-Origin 标头，即表示完成。

由索引模型根据 Issue 内容生成。