Add ability to download all Patient Data as Plaintext

[mattwalo32]

Tobias mentioned that this feature is important because the internet isn't a given in Jordan llike it is in the US. If there are "regional struggles", the internet could be turned off by the government. We should have the option to download all patient data so that we can periodically create backups if we lose internet access.

Points to consider:

• The dataset could be very very large. Might take a long time to download
• The data is encrypted. So we'd need to decrypt it before sending
• MongoDB Atlas should already be making periodic backups

Due to these considerations, I don't think that this should be a button on the website. Instead, we can make a decrypter that takes the encrypted DB backup and the encryption key as an input and produces the plaintext.