Add Jira Links Endpoint

[cthenderson]

Adding additional endpoint for fetching JIra issue links.

[fprimex]

Hi, thanks for the contribution. The zdesk_api.py is generated from zdgen. I would like to leave this open for those who might be looking for the same thing, then fix this over in zdgen. They've changed the docs layout and I've started working on updates to account for that.

[fprimex]

I have a branch created with an updated zdgen:

https://github.com/fprimex/zdesk/tree/doc_site_update

Can you see if this will work for you? They have changed a lot of things (for the better) while migrating their docs site, so you may have to make some changes. Notably, every id argument they had became more descriptive. Instead of id they now have, e.g., ticket_id.

[cthenderson]

Thanks for getting this update in. I noticed the call method was causing an infinite loop when I passed in path=/api/v2/jira/links, get_all_pages=True. I created a PR with the doc_site_update as the base to handle all of the paging responses.

#64