Improve time navigator

[LanesGood]

No description provided.

[vgeorge]

We replaced the slider and removed the date picker. Now the app is showing pagination-like "time navigator", with forward and backward buttons for hour or daily steps.

I suggest the additional changes:

• Add button for going to the start/end of the time range (depends on Add manifest json file to storage bucket with time range #40)
• Add date picker to travel to an specific time more easily
• Add "play" button to advance hour steps automatically (see Play animation #26)
• Improve styles

cc @LanesGood @kamicut