add data storage file and updated README

[alchin2]

No description provided.

[tsepuri]

• input_lookit.json needs to be updated to read input_lookit_study_data.json
• the initial Lookit JSON processing only converts it to lookit_study_data.json, level-trials_source-lookit_data.csv is only created during the iCatcher processing but I can see the argument for detaching those. we would just have to update part 3.