Upgrade the Zoom functionality

[KM-Hanson]

The desired functionality:

When selecting business detail from the list....

• map centers on the selected business
• store the current zoom level selected by the user
• when users selects 'back to list', return to that zoom level previously selected by the user, so that the list is always the same

When changing categories....

• Reset map position and zoom to the defaults
• This part can be upgraded when we move beyond the Google sheet data source