Rework previous button to handle cases where users accidently leave the annotation page

[Sean1572]

Currently if the user leaves the annotation page, returning to the data page, they cannot return to the previous page they worked on, only the first since webpages only track the file they started on.

Instead we remove the code in the render function of data.js that resets the previous_link lists and instead let it persist on the browser. Then we will need to figure out a way to determine when users want to go back to their previous work or start a new work session. That way if the user wants to back into their work, they are able to do so in a logical manner.