fix: add tooltip, misc bug fixes, a11y fixes

[joannaong]

Description

1. added "inspect file" tooltip on dataset single page
2. Navigating to a 404 page displays breadcrumbs
3. Tooltip over “login” is misaligned
4. about page mobile heading
5. Style polish on cid card data single page and added a feature flag to use mocks
6. Add back card-list-block
7. Implement keyboard tabbing focus ring on buttons and links except for typeahead (Nauras will do on a different ticket)

Screenshots

Ticket link

[timelytree]

Tooltip should never touch the edge of the screen. Let's give it an offset of ~1rem?

[nicole-code]

Changes made that address this tickett all look great to me locally!
Thanks @joannaong & @timelytree !

[nicole-code]

These may be a bit nit picky @timelytree and @joannaong but here goes ->

1. This is happen when I tab over the page that I'm on - looks like the focus ring is cut off. Not sure if this is too nit picky

2. If I'm tabbing through through the site for the first time, I always have to hit the enter key twice on the Filters button before the filter panel opens
3. If the Filters panel is open and I don't close it, once I tab off of the panel, the panel still stays open which obstructs the view of the datasets list. I know this is working as expected but I think, if we have time, we could add something where if the user tabs off of the panel, the panel closes.

Let me know what you all think! I can create tickets for any of these if we want to address then :)

[joannaong]

These may be a bit nit picky @timelytree and @joannaong but here goes ->

1. This is happen when I tab over the page that I'm on - looks like the focus ring is cut off. Not sure if this is too nit picky

2. If I'm tabbing through through the site for the first time, I always have to hit the enter key twice on the Filters button before the filter panel opens
3. If the Filters panel is open and I don't close it, once I tab off of the panel, the panel still stays open which obstructs the view of the datasets list. I know this is working as expected but I think, if we have time, we could add something where if the user tabs off of the panel, the panel closes.

Let me know what you all think! I can create tickets for any of these if we want to address then :)

@nicole-code

1. Fixed
2. This will be part of the typeahead ticket. when i remove the typeahead component, the enter works fine. You can confirm by clicking esc after the typeahead dropdown opens. Once esc is clicked, only clicking enter once works. Can you pls note on the typeahead tabbing ticket?
3. I think we can skip this? blur in here will be hard to detect

[nicole-code]

Looks good on my end ! @joannaong @timelytree !