linkbox: fix downloading files by using web API - fixes #8665

The Linkbox open API (/api/open/file_search) no longer returns download
URLs, breaking all downloads. This switches to using the web API
(/api/file/my_file_list/web) which requires email+password authentication
but returns working download URLs.

This will unfortunately require changing your existing rclone config.

- Add email, password, and web_token config options
- Add web API login via /api/user/login_email with token caching and retry
- Create separate CDN HTTP client with HTTP/2 disabled and browser
  User-Agent to avoid CDN fingerprint blocking
- Remove searchOK regex and name-filtering (web API doesn't support it)

docs/content/linkbox.md

@@ -12,6 +12,17 @@ Linkbox is [a private cloud drive](https://linkbox.to/).
 
 Here is an example of making a remote for Linkbox.
 
+You will need:
+- An API token from https://www.linkbox.to/admin/account
+- The email and password for your Linkbox account
+
+**Note:** As of v1.74, email and password are required in addition to
+the API token. The API token is used for uploads and modifications,
+while email/password authentication is used for listing and
+downloading files. If you have an existing Linkbox remote, you will
+need to reconfigure it with `rclone config` to edit the remote and add
+the email and password.
+
 First run:
 
 ```console
@@ -40,12 +51,24 @@ Storage> XX
 Option token.
 Token from https://www.linkbox.to/admin/account
 Enter a value.
-token> testFromCLToken
+token> YOUR_API_TOKEN
+
+Option email.
+Email for login
+Enter a value.
+email> your@email.com
+
+Option password.
+Password for login
+Enter a value.
+password> YOUR_PASSWORD
 
 Configuration complete.
 Options:
 - type: linkbox
 - token: XXXXXXXXXXX
+- email: your@email.com
+- password: *** ENCRYPTED ***
 Keep this "linkbox" remote?
 y) Yes this is OK (default)
 e) Edit this remote