feat(server): add internal --path-prefix flag for client/server mode

[knqyf263]

Overview

This PR introduces a new internal flag --path-prefix for client/server mode, allowing customization of the API endpoint prefix. This feature is currently intended for internal use only and will not be exposed in the CLI help output.

$ trivy server --path-prefix myprefix

$ trivy image --server http://localhost:4954 --path-prefix myprefix debian:11

Changes

• Add a new --path-prefix flag to customize the API endpoint prefix in server mode
• Implement logic to
  • apply the custom prefix to all server endpoints
  • apply the custom prefix to all client requests
• Ensure the flag is hidden from CLI help output
• Hide deprecated/removed flags in the configuration document
• Add integration tests

Rationale

This change is necessary for internal purposes, but we want to maintain flexibility for future modifications. By keeping it hidden, we avoid potential issues with backward compatibility if external users start relying on this feature.

Example

Current endpoint structure:

<baseURL>[<prefix>]/<package>.<Service>/<Method>

<prefix> can be customized via --path-prefix.

Notes

• This feature will not be documented in public-facing materials
• We may consider exporting this flag in the future if there's significant community demand

Checklist

• I've read the guidelines for contributing to this repository.
• I've followed the conventions in the PR title.
• I've added tests that prove my fix is effective or that my feature works.
• I've updated the documentation with the relevant information (if needed).
• I've added usage information (if the PR introduces new options)
• I've included a "before" and "after" example to the description (if the PR is a user interface change).

[afdesk]

LGTM!

[knqyf263]

@DmitriyLewen It needs approval from someone who has write permission. Would you take a quick look?

[DmitriyLewen]

LGTM