Throttle requests to mitigate RateLimitExceededExceptions (#2145)

This introduces a throttling of requests to the Github REST API (1s for writes, 0.25s for reads, configurable)
to mitigate secondary rate limit errors and comply with Github's best practices:

https://docs.github.com/en/rest/guides/best-practices-for-integrators?apiVersion=2022-11-28#dealing-with-secondary-rate-limits

github/GithubIntegration.pyi

@@ -18,12 +18,15 @@ class GithubIntegration:
         integration_id: Optional[Union[int, str]] = ...,
         private_key: Optional[str] = ...,
         base_url: str = ...,
+        *,
         timeout: int = ...,
         user_agent: str = ...,
         per_page: int = ...,
         verify: Union[bool, str] = ...,
         retry: Optional[Union[int, Retry]] = ...,
         pool_size: Optional[int] = ...,
+        seconds_between_requests: Optional[float] = ...,
+        seconds_between_writes: Optional[float] = ...,
         jwt_expiry: int = ...,
         jwt_issued_at: int = ...,
         jwt_algorithm: str = ...,