[RFC] (improvement)Remove CQL binary protocol v3

[mykaul]

It's not needed. v4 or above is supported everywhere.

Pre-review checklist

• I have split my patch into logically separate commits.
• All commit messages clearly explain what they change and why.
• I added relevant tests for new features and bug fixes.
• All commits compile, pass static checks and pass test.
• PR description sums up the changes and reasons why they should be introduced.
• I have provided docstrings for the public items that I want to introduce.
• I have adjusted the documentation in ./docs/source/.
• I added appropriate Fixes: annotations to PR description.

[mykaul]

This branch is no good, contains items from #630 , which is not merged yet :-/

(and might need some additional fix, we'll see).