PLAT-75 Jobqueue migration for RefreshLinksJob and RefreshLinksJob2

This job migration was two in one. The original `RefreshLinksJob2` was created which then launched one `RefreshLinkJob` for every back link to the template retrieved in `LinksUpdate`.

This pull request migrates `RefreshLinksJob` to a task with the name `RefreshLinksForTitleTask` and migrates `RefreshLinksJob2` to `BatchRefreshLinksForTemplate`. The new naming I think better reflects what is happening with the tasks.

The new tasks also have some basic testing in place. The structure of the code was also cleaned up to be less verbose.

/cc @nmonterroso @Wikia/platform-team 
This can be removed, since it's overriding BaseTask with an identical function.