Splitup cassandra connection abstraction

[rukai]

This PR only changes test code. This PR contains no functional changes to the tests.

cassandra/connection.rs is split up into connection.rs, scylla.rs, cdrs.rs and cpp.rs. This is done by introducing ScyllaConnection, CdrsConnection and CppConnection types that hold all wrapping logic for each driver.

I attempted to keep this as straightforward as possible, however there were some important renames that needed to be done, so I included those in this PR. The renames include:

• CdrsTokio -> Cdrs - Shortened form since we write this so much
• datastax -> cpp - while the driver is written by datastax, so is other drivers, so its a bit ambiguous. Cpp matches the naming style used by the kafka drivers abstraction.
• Types like ScyllaBatch are renamed to just Batch since its no longer ambiguous because they live in their own scylla specific module now.

Additionally the TIMEOUT constant is changed to include the whole Duration type. Previously it was not clear what unit of time the timeout was in.

[codspeed-hq[bot]]

CodSpeed Performance Report

Merging #1680 will not alter performance

_{Comparing rukai:splitup_cassandra_connection_abstraction (b1d6747) with main (11c0d58)}

Summary

✅ 39 untouched benchmarks