Consider storing jobs without the job ID in the option name

Since we don't leverage the WP core `get|update_option` methods any longer, we don't necessarily need the unique job identifier in the option name. This causes issues on some hosts that artificially limit the options table to 64 characters rather than the default 255 since WP 4.4.

We can consider storing the job ID as part of the job data instead, then adjusting our SQL to look for this ID when getting the job since the option names will be duplicated.

Will also need an upgrade in plugins that implement this for the existing job storage. This can be used as a stop-gap until considering whether or not we want to move job storage to a custom table.

* **See**: [Slack convo](https://skyverge.slack.com/archives/C13FY91F0/p1503682334000013), [HS convo 50837](https://secure.helpscout.net/conversation/415440462/50837?folderId=46422), [ZD convo 613896](https://woothemes.zendesk.com/agent/tickets/613896)