✨ [FEATURE]: Add file upload to button

[thinkjrs]

Is your feature request related to a problem? Please describe.
Clients have requested the ability to add additional files that provide context, relevance and other data for campaigns.

In particular, many clients wish to upload targeting CSVs of their current audiences, customers and leads.

Describe the solution you'd like

• Component: We should have a file upload section underneath the asset upload.

  This should show a link to each file after upload, truncated for the button's width.

• Exported function to send POST and DELETE requests to specified storage API route using the JavaScript fetch API.

Additional context
Tincre employees can follow along within the larger milestone in Gitlab.