Update poll

@mupuf I need to add an additional test for the bug search patch I have, but I'll get that done tomorrow. Just wanted to get this up for feedback.

In regards to that, the way we had search_bug_ids set up for Jira doesn't work properly due to there being an upper limit of 1000 issues pulled in a single query, so the patch I have fixes that. I'm guessing we didn't notice this because we add the open_bugs from the DB and the new issues get returned first when querying Jira.

For the polling only updated bugs, I kept the followed_bugs and open_bugs methods, as they may be useful elsewhere, and added the updated_bugs method to return only bugs that have been updated. I'm not sure if we want to modify poll bugs to take an additional argument to specify polling all bugs, or only updated ones. Not sure if there is a use case for that.

I've tested it all out locally and it all is looking good though. This will greatly reduce the unnecessary polling we're currently doing :)