feat: add org selection page

[sutterj]

Pull Request

Proposed Changes

• Closes #130
  • add selection page for org
  • make search components generic
  • separate welcome, org, and fork headers
  • add orgs hook

Readiness Checklist

Author/Contributor

• [ ] If documentation is needed for this change, has that been included in this pull request
• [X] run npm run lint and fix any linting issues that have been introduced
• [X] run npm run test and run tests
• [ ] If publishing new data to the public (scorecards, security scan results, code quality results, live dashboards, etc.), please request review from @jeffrey-luszcz

Reviewer

• [X] Label as either bug, documentation, enhancement, infrastructure, maintenance, or breaking

[sutterj]