Removing deprecations in 4.0

[Stranger6667]

In this issue, I'll collect all breaking changes (from the behavior & public API point of view).

Using the endpoint term in our public API

• HookContext.endpoint
• Case.endpoint

Auth

• Defining AuthProvider.get with a single argument

CLI

• --stateful-recursion-limit
• --store-network-log
• --pre-run
• --show-errors-tracebacks - fix grammar
• --contrib-unique-data

Engine

• Restructure SerializedTestResult so it has a single source for request / response pairs. E.g. every result has a set of request/response pairs and other data structures refer to them by numeric id
• Remove schemathesis.runner.prepare
• Per-operation seed

Data generation

• Include method into generation_config
• Switch to \x00-\x7f character range for headers by default.

Hooks

• Deprecated hook names (there will be some, e.g. before_generate_case)
• unique_data