[FEA]: Take multi-modal html files as input

[chenyang-shanghai]

Is this a new feature, an improvement, or a change to existing functionality?

New Feature

How would you describe the priority of this feature request

Currently preventing usage

Please provide a clear description of problem this feature solves

It's quite common for web system offerring online document(such as PRD) editing functions(wysiwyg editor). So there is a need that we save all the pages from the web online editor as html files.

Describe the feature, and optionally a solution or implementation and any alternatives

It will be very helpful that nv-ingest could suppor html files as input.

Additional context

In the html file, there're a lot of pictures,which is very important, and should not be ignored.