fix: Add layer of security and download p7zip-full lib on docker

[AyakorK]

🎩 Description

This PR adds the library p7zip-full to the dockerfile to fix the issue of the data that were not exporting on user profile.
This also adds a layer of security to the code to ensure to generate the file if it doesn't exist to avoid errors.

📌 Related Issues

Link your PR to an issue

• BUG - Error on DownloadYourDataExportJob

Testing

Describe the best way to test or validate your PR.

TO SETUP YOUR APP

• Please use DOCKER you absolutely need it
• If you already had setup a docker instance of decidim-tou in the past please run make teardown
• If you want to be sure you can run make build
• Run the command make run to setup your app
• Once it's setup please make sure you access to your platform using the url https://localhost:3000

TEST THE FEATURE

• Log in as a user (or admin)
• Access to your profile using "My Account" button
• Access "Download your data"
• Hit the button
• Access https://localhost:3000/letter_opener
• Make sure you received the mail with your data

IF YOU RECEIVED IT

• Please open your folder using the password in the mail
• Make sure everything works correctly and that you received all your data

IF YOU DIDN'T RECEIVE IT

• Please access https://localhost:3000/sidekiq
• Log as [email protected]
• Access to your retries and provide us the error

Tasks

• Modify Dockerfile and Dockerfile.local to add p7zip-full
• Modify the service to add a layer of security