Please add a field in the Library module for "alt text" displayed on web pages

I'm a great believer in managing data at source. It would be very useful to be able to describe an image for visually-impaired web users in Lightroom and have this metadata embedded in the image, so that platforms like WordPress can read it and add it automatically to the Alt field in its media library database on upload. I know you have custom fields for websites like 500px, so I hope this wouldn't be too difficult