add tracks property to the IGVBrowser component

[fossilfriend]

• [ ] 1. create branch for this issue, from the menu on the right
• [ ] 2. add tracks property to the IGVBrowser component. The type should be an array of items of the type IGVTrackProps
• [ ] 3. define (and export, but not as the default export) the IGVTrackProps interface in types/Tracks.tsx

  HINT: search the GenomicsDBWebsite project for the interface

• [ ] 4. update reference to IGVBrowser component in the App to include the tracks property and set the value to the constant, imported track config value
• [ ] 5. when done, close the issue using the commit message (see https://stackoverflow.com/questions/1687262/link-to-the-issue-number-on-github-within-a-commit-message)

  NOTE: this will not actually close the issue, but when the pull request is approved, it will automatically close the issue

[fossilfriend]

Revised Step 2, above

• [ ] create interface defining type TrackBaseOptions in types/Tracks.tsx instead of the IGVTrackProps suggested above
• fields pulled from this worksheet

Revise Step 1, above

The tracks property of IGVBrowser should be an array of TrackBaseOptions for now