Add Icons for resources and data sources

[ecanault]

Hi,

This is another request to add Icons for resources and data sources.

Description

Jamf Pro API Endpoint for Icons is described here:

• POST request to upload a new icon https://developer.jamf.com/jamf-pro/reference/post_v1-icon
• GET request to download an existing icon https://developer.jamf.com/jamf-pro/reference/get_v1-icon-id

Endpoint URL: https://yourServer.jamfcloud.com/api/v1/icon/{id}

Sample request body for POST with cURL:

curl --request POST \
     --url https://yourserver.jamfcloud.com/api/v1/icon \
     --header 'accept: application/json' \
     --header 'content-type: multipart/form-data' \
     --form file=@icon.png

Required parameter for GET: id

Sample Go code for each method is available on the pages above, but I don't have the knowledge to develop this by myself.
I hope I'm doing it the good way to ask this, and thank you for creating a PR if you find this enhancement helpful!