[FEATURE] Automatically delay requests based on the Retry-After header value

[Stranger6667]

Is your feature request related to a problem? Please describe.
Often Schemathesis tests fail because of rate limits and generally are not executed as expected and don't test the service properly.

Describe the solution you'd like
There is a manual rate limiting (in #910), but it could happen that Schemathesis hits the limit anyway, for example, if no rate limit is set in CLI or just unexpected.

As a secondary measure, Schemathesis can read the Retry-After header and delay requests automatically.

It could be activated via e.g. the --rate-limit=auto CLI option

Describe alternatives you've considered
Just a manual rate limit, but it could still fail for different reasons.

Additional context
There are a few unresolved issues:

• Should it be the default behavior? If the delay time is too long, then it could unexpectedly slow down the tests.
• How to indicate that delay is applied? Should it be reported somewhere?
• What if there is an error in the 429 response (e.g., the response does not match the schema) - how to report it?
• Should we have a way (e.g. CLI option) to control such behavior