* initial consolidation of rate limiting code to request package to reduce bespoke code implementation
* continued
* finish abstraction
* lint
* exchanges: fix tests
* linter: fix
* poloniex: fix auth rate limit not being set
* ratelimiter: convert from token to weight
* glorious: nits addressed with fire
* linter: rip
* change func name set -> get
* fix test
* derbit: impl
---------
Co-authored-by: Ryan O'Hara-Reid <ryan.oharareid@thrasher.io>
Refactoring the timeout retries into a more general 'retry policy' with
support for retrying on HTTP 429 (Too Many Requests) and other responses
with a `Retry-After` header
The delay between requests is controlled by a combination of a 'backoff'
(currently only a simple linear backoff), and honouring the
`Retry-After` value (longest delay wins)
This makes the 'rate limiter' an optional argument as well, removing the
use of `nil` when one isn't supplied
Signed-off-by: David Ackroyd <daveo.ackroyd@gmail.com>