Add Redis Connection String Attribute to scaleway_redis_cluster Resource

[jremy42]

Description:
Currently, the scaleway_redis_cluster resource does not provide a way to obtain the full Redis connection string directly from its attributes. This connection string should consolidate the necessary details—namely, the host, port, and the already provided password—into a single, easy-to-use string.

Proposed Solution:

Create a new attribute (e.g., connection_string) for the scaleway_redis_cluster resource.
Construct the connection string using the format:

redis://:<password>@<host>:<port>/<db_number>

For example, if the password, host, and port are provided as attributes, the output might look like:

redis://:[email protected]:6379/0

Ensure that this change does not introduce any security risks, as the password is already available as an attribute.