StandardBullhornData Should Properly Handle Rate-Limiting

[bh-mhenrichs]

The REST API is behind a gateway that will rate-limit connections that burst too high in traffic, and the SDK does not properly handle the 429 Responses. The methods that make REST calls into our API should properly handle a 429 response.

The functions:

• performGetRequest
• performPostRequest
• performCustomRequest

Approach:

• When receiving the 429 response, the SDK should sleep for a second and then retry the request. Note that this should not be susceptible to the API_RETRY limit, so it can't simply be added to handleHttpStatusCodeError without some minor refactoring to that function.