Client: Split trial.json into diff files

[mickahell]

Summary

Export circuits and texts from trial json into diff files.
Details about folder organization : #122

Details and comments

• Reorganize into trial_uuid folders
• Simply to have any get using the get() function and any save to use the save() function
• Export circuits
• Export texts
• Update unit tests

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Closes #122

[mickahell]

@IceKhan13 @AnsahMohammad
I'm pretty sure it has a better way to encode and decode external part of trial.json (maybe even adding a ref from trial.json to go read external file so then encoding and decoding can be done only once for all).

[IceKhan13]

@mickahell put this PR as ready for review when you are done :)

Thank you! Already looks good :)

[mickahell]

@IceKhan13 @AnsahMohammad ready for your review :)

[IceKhan13]

Let's go! 🚀