docs: Remove base-url (#9056)

The web module doesn't support base-url as of now.

Author: psibi

docs/common/arguments.md

@@ -62,7 +62,6 @@ Dashboard containers accept multiple arguments that can be used to customize the
 | system-banner              | -                             | When non-empty displays message to Dashboard users. Accepts simple HTML tags.                                                                                             |
 | system-banner-severity     | INFO                          | Severity of system banner. Should be one of `INFO\|WARNING\|ERROR`.                                                                                                       |
 | kubeconfig                 | -                             | Path to `kubeconfig` file.                                                                                                                                                |
-| base-url                   | /                             | Base URL used to serve web app.                                                                                                                                           |
 | v                          | 1                             | Number for the log level verbosity (default 1)                                                                                                                            |                                                                                                                                                                                                                                                                                                |
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 _Copyright 2019 [The Kubernetes Dashboard Authors](https://github.com/kubernetes/dashboard/graphs/contributors)_