Create data sync example in tutorial

[tahpot]

It is possible to syncronize data between two databases in different application contexts.

This was previously implemented in the https://github.com/verida/practitioner-emr-web project allowing a user to sync their health records between the Vault and the EMR application.

Here is the code in the EMR web application that generates the Vault message requesting data to be syncronized.

The tutorial needs to add the ability for to generate this type of data sync request, to create a local encrypted database in the tutorial context and sync it with data from the Vault (perhaps the contexts or credentials?).

[tahpot]

@nick-verida I have added an example of this in the web sandbox:

https://github.com/verida/web-sandbox/pull/28

It doesn't actually work in the Vault, as there is a bug. Created an issue here:
https://github.com/verida/vault-mobile/issues/478