ser: use rust-driver's builtin serialization for simple types

[muzarski]

Previously, we would reimplement a serialization logic. It was a copy from rust driver, with the typechecks excluded.

In this PR, we get rid of the repeated code. To skip the typechecks (or rather, to make the typechecks always pass), we simply provide a valid ColumnType to SerializeValue::serialize().

This is a kind of hack, but thanks to that we don't have to reimplement serialization logic.

Pre-review checklist

• [x] I have split my patch into logically separate commits.
• [x] All commit messages clearly explain what they change and why.
• [x] PR description sums up the changes and reasons why they should be introduced.
• ~[ ] I have enabled appropriate tests in .github/workflows/build.yml in gtest_filter.~
• ~[ ] I have enabled appropriate tests in .github/workflows/cassandra.yml in gtest_filter.~

[muzarski]

Isn't it possible to remove CassCqlValue entirely?

I think it is possible. The main obstacle are udts, collections and tuples. We would need to construct a valid ColumnType for each of these, and a nested ColumnType may be expensive to construct (some allocations). I think that there is no other way to use a builtin rust-driver's serialization with typechecks skipped for these types.

[Lorak-mmk]

Ok, let's keep the approach from this PR

[muzarski]

Actually, I think we could simply have a wrapper over CqlValue.

[muzarski]

Actually, I think we could simply have a wrapper over CqlValue.

Give me a second, I'll investigate it and update this PR in case it's possible.

[muzarski]

Nvm, I don't think there is much sense to introduce a wrapper over CqlValue, since we would need to match variants that can never be created via cpp-rust-driver API (e.g. there is no way to create a CqlValue::Counter() value).

I think that we can merge it as is.