Add a maintenance icon

[joshwooding]

Area

UI Components

The problem

When the system goes down for maintenance, we want to show a banner to notify users. Right now there isn't a suitable icon.

The solution

Add an icon to represent maintenance e.g. a wrench or tools.

Alternatives and examples

.

Are you a JPMorgan Chase & Co. employee?

• [ ] I am an employee of JPMorgan Chase & Co.

[pseys]

Can be worked on at the same time as #3646