Add card icons and 'back to top' button

[braxex]

Summary

We need icons for browse cards and a button on the browse page to take users back to the top. This PR adds both. Closes #77 Fixes #56 (issue)

Type of change

• [x] New feature (non-breaking change which adds functionality)

How To Test

1. Pull and run app
2. Observe the pleasant way the back-to-top button appears and disappears, and the gentleness of its scroll.
3. Bask in the beauty of the icons on the cards.

Checklist:

• [x] My code follows the style guidelines of this project and has no linting errors
• [x] I have performed a self-review of my code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation, including any applicable ADRs
• [x] My changes generate no new warnings
• [x] I have added tests that fail without these changes
• [x] New and existing tests (unit, integration, accessibility) pass locally
• [x] Documentation updated
• [ ] If there are security concerns they are addressed or ticketed after being discussed

[codeclimate[bot]]

Code Climate has analyzed commit 61db7275 and detected 0 issues on this pull request.

The test coverage on the diff in this pull request is 98.0% (80% is the threshold).

This pull request will bring the total coverage in the repository to 95.3% (0.2% change).

View more on Code Climate.

[TheDanMiller]

@braxex two questions, not blockers.

1. Can we delay when it pops a little bit> Maybe show the button when the apply filters moves out of sight or some other landmark like that
2. Can we transition it out a little sooner, IMO it seems like its visible just a tad bit too long.

[braxex]

@TheDanMiller

Can we delay when it pops a little bit> Maybe show the button when the apply filters moves out of sight or some other landmark like that Can we transition it out a little sooner, IMO it seems like its visible just a tad bit too long.

Yep, we can tweak both of these when everything is finalized.