Save and reload system test

[ChasNelson1990]

Describe the test

We need a series of system tests and visual tests, using BrowserStack Automate, Selenium and Percy Snapshot (@joshuajames-smith), for the following:

• saving annotations (for each toolbox)
• loading saved annotations (for each toolbox)
• editing saved annotations (and resaving and loading) (for each toolbox)

*NOTE: I recommend splitting this issue into one for each annotation for easier tracking of progress but will leave this to @philipjackson ***

[joshuajames-smith]

Relates to gliff-ai/dominate#493