Databases: Add Valkey/Redis as a database for load generation

[dbazhenov]

Add another database, just like MySQL, PG, MongoDB. To be able to generate load and manage it.
Since our dataset is in JSON format, we can simply store it as strings for PR and as hash for Repos

Add a new database type - Valkey/Redis.

1. Add an option to create a connection
2. Add import of dataset.
3. Add load functions.

The task is of medium complexity, you can do by analogy with MySQL/Postgres