Remove pul-assets dependency

[sandbergja]

What maintenance needs to be done?

Remove pul-assets dependency

Level of urgency

• High
• Moderate
• Low

Why is this maintenance needed?

This is the only non-deprecated application that uses PUL Assets. We already use Lux in this application, which has more up-to-date branding, and is more widely supported.

Acceptance criteria

• We no longer use the pul-assets gem

[kevinreiss]

Noting that DSS does not actually use LUX at the moment. The header/footer is provided by this gem if I follow the code.