Associate unassociated authors with Bamboo users

From: https://support.atlassian.com/browse/BSP-7201

We've recently fixed matching users with authors by email address (especially for git). However existing, non-associated author data was not associated after those changes.

Some ideas for implementation:

• upgrade task that would attempt to associate non-associated author data with Bamboo users using all existing methods
• administrator available action that would do the above
• administrator available action that would do the above for a given user