[New icons]: Add new icons for clipboard and resizing

Please add the icons requested in this [ticket](https://warthogs.atlassian.net/browse/BRND-3246), along with the related icon set.
The icons have been uploaded to the asset manager here: https://assets.ubuntu.com/manager?tag=brnd-3246

## Icons
clipboard

clipboard-chart

clipboard list

maximize

minimize

Review the BRND-3246 ticket and the five uploaded assets in the Ubuntu asset manager, then compare them with the repository's existing icon set. Done means the clipboard, clipboard-chart, clipboard list, maximize, and minimize icons are added consistently to that set and available through the framework.

Written by the indexing model from the issue text.