Feature Request: Support URL rewrite

[hehaoqian]

In order to more easily handle downloaded schema in a company network,
I hope there is a cmdline to configure URL rewrite,
so that the schema under the official URL, such as https://www.schemastore.org/,
can be rewritten to a company mirror URL.

The reason is that external websites are often blocked by company firewall.

Some examples for the URL rewrite in other projects:

• https://mise.en.dev/url-replacements.html
• https://bazel.build/reference/command-line-reference#common_options-flag--downloader_config