Conference-app-2020: Add search item index and sort items.

[roana0229]

Kind (Required)

• Improvement

  Overview (Required)

• Add search item index of speaker and session.

  • The same index is displayed only once.
  • The index is displayed in the same way as the time in the timetable.
• Sort by speaker name, session title.

## Links

-

[Pluu]

🙋🏻‍♂️

[FujiKinaga]

@Pluu
Thanks again! Assigned 👍