Add 'Take Sourcegraph to your [code host]' popover

Created by: tjkandala

Closes #14199 (closed). Part of RFC 221

• - Convert GoToCodeHostAction to function component
• - Implement popup popover
• - Remove chrome extension toast
• - Implement focus trapping for modal
• - Implement hover tracking (5 hovers seen by user before displaying popup)
• - Storybook
• - Integration testing
• - Improve CSS
  • - SVG sizing
  • - Popover arrow

Interaction

Popover fade in on click

Keyboard navigation, "Remind me later"

Popover visuals

@AlicjaSuska The "arrow" is a square rotated 45 degrees and 50% hidden by the popover. This approach is good for responsive popovers since it's mostly the same styles for each direction, but it doesn't align 100% with the design. I'll revisit the arrow after finishing the remaining issues.