Add support for file:// protocol in plugin URI

### Version report

Jenkins and plugins versions report:

Jenkins 2.303.1; no plugins installed

### Reproduction steps

1. Run Jenkins docker LTS image
2. Open a shell in the image
3. Try to install a local hpi file by running this command: `jenkins-plugin-cli -p git:4.8.2_CMT:file:///usr/share/jenkins/ref/plugins/git-4.8.2_CMT.hpi`

### Results

Expected result:

I expected to see the plugin and all of its dependencies get installed.

Actual result:

I got an error:

`Unable to resolve plugin URL file:///usr/share/jenkins/ref/plugins/git-4.8.2_CMT.hpi, or download plugin git to file: URI does not specify a valid host name: file:///usr/share/jenkins/ref/plugins/git-4.8.2_CMT.hpi`

I believe the problem is that jenkins-plugin-cli does not support the file:// protocol. If there is some other known way to install a local hpi file using jenkins-plugin-cli dependency resolver, let me know.