Word outputs including images #1272

Prework

• Read and abide by gt's code of conduct and contributing guidelines.
• Search for duplicates among the existing issues (both open and closed).

Proposal

Describe the new feature clearly and concisely. If applicable, write a minimal example in R code or pseudo-code to show input, usage, and desired output.

Currently html outputs support images as cell content. I would like to do the same with word documents (and possible other formats other than html?)