File upload has multiple accessibility problems

[BryceStevenWilley]

(See A11Y-12)

[ekressmiller]

The krajee Bootstrap File Input plugin (https://github.com/kartik-v/bootstrap-fileinput) is the source of these barriers. The most effective long-term solution would be to replace it with a simpler, accessible file upload pattern that uses the native browser file input, which is accessible by default. If replacing the plugin is not feasible, the following individual issues should be addressed:

• remove "tabindex=500" from the Remove and Browse buttons so they follow the natural tab order,
• ensure the Browse element is announced as a button by screen readers,
• add a label to the read-only input,
• add "alt=" (empty) to uploaded image thumbnails since they are decorative, and
• increase the color contrast of the placeholder and file info text.