✨New welcome flow for importing settings from other browsers

[imptrx]

Issue tracker: brave/brave-browser#1530
Spec: brave/brave-core#2679 (comment)

Changes

• Inline import option in the welcome flow for importing settings from other browsers
• Dev Concern: I copied the Select into "features/welcome" since we have multiple "screens" in welcome relying on it - it didn't make sense to have all of them cross-referencing a shields component (I am assuming we can lift it to a general directory when we migrate our stories to core)
• Quick view:
  

Test plan

• brave://welcome should still load properly when loaded
• Should be an inline option to pick a browser to import settings from via drop down
• "Import" button is disabled unless an valid option is chosen
• Import button should lead to next step of on-boarding process

Link / storybook path to visual changes

• https://brave-ui-bpu9szh0x.now.sh/?path=/story/feature-components-welcome--page

Integration

• Does this contain changes to src/components or src/

  • Will you publish to npm immediately after this PR, or wait until sometime in the future?
  • Incompatible API change to something existing (major version increase)
  • Adding new backwards-compatible functionality? (minor version increase)
  • Fixing a bug backwards-compatibly? (patch version increase)

• Does this contain changes to src/features for brave-core?

  • Are there non backwards-compatible changes required for brave-core? Do not merge until brave-core PR is approvable. Link to brave-core PR:
  • Will you create brave-core PR to update to this commit after it is merged?
  • Wants uplift to brave-core feature branch?
    • When uplift-approved, merge to brave-core-0.VV.x feature branch
    • Create additional brave-core PRs for each feature branch to update commit

[imptrx]

Should be no breaking changes in brave-core as it's mostly storybook changes plus duplication of a component 🙈

[bsclifton]

This is amazing 😄 Doesn't look like it would be too hard to integrate into brave/brave-core#2679 after this is done

[rossmoody]

👍

[cezaraugusto]

++