Added footer based on Challenge Platform - related card #1363

None

Updated CSS Added Images Added layout _footerv2.html.eex Updated layout root.html.eex

See card #1363

Checklist

[x] PR is assigned to a project: Challenge_gov Board
[x] PR is assigned to a milestone: current sprint
[x] GH issues are assigned to the PR (under Development section on the right hand side)
[x] PR is assigned a reviewer, and requires code review and approval by a teammate
[ ] New functionality is tested and all tests are green
[ ] I have added unit tests for new functionality or updated existing tests for changes.
[ ] I have updated the documentation/README accordingly, if necessary.
[ ] If you have DB migration, it is a "safe" migration and you've confirmed it can be rolled back.
[ ] If applicable, Controllers modified contain appropriate authorization plugs
[x] This PR has been reviewed by at least one other team member.

GSA / Challenge_gov