Support image paths that are different on the server than the local system

[LeeHolmes]

Describe your feature request

When you are using an engine like Hugo, it is common to have a local image path on your computer like "c:\hugo\static\images\hello.png" which then turns into an absolute image path like "/images/hello.png" when published. Marktext's current 'prefer relative image path' feature doesn't support this scenario.

A feature to 'Maintain server paths during editing and preview' would address this.

Additional context

This issue to be accompanied shortly by a PR that implements this feature.