cass_data_type: frozen support

[muzarski]

Fix: https://github.com/scylladb/cpp-rust-driver/issues/49

This PR adds information about whether the type is frozen (applicable for collections and UDTs only).

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.~