Icon Library: Determine naming strategy for icons

[jessicawoodin]

This work will depend on the results of #145 and if/how we're able to import icons from VADS.

Icon names should:

• [ ] Be app agnostic - describe the icon, not the use case.
• [ ] Be consistent for designers and engineers.
• [ ] Be consistent with VADS.

Any other requirements from engineering?

To dos

• [ ] Research how other design systems name icons
• [ ] Research how VADS names icons
• [ ] Document our naming strategy

[jessicawoodin]

Icon names will be identical to VADS/USWDS. Closing this ticket.