retain color selections in browser session

[interim17]

Description

Users would like their color choices to be saved in the browser so that they can navigate to and from a trajectory after making color selections, and not lose their choices.

Part of closing #510

• differentiate default color settings from changed color settings #579
• ability to store current ui display data in local storage #580
• function to compare if agent tree structures match #581
• ability to retrieve stored color settings from browser storage #582
• restore defaults button/ ability to toggle between default and changed color settings #583

Acceptance Criteria

After making color selections, a user in the same browser session should be able to navigate back to that trajectory and find their color choices have been remembered and applied.