Bastion: adding product and repository sync functionality.

This commit adds bulk actions for products and repositories including
removal, syncing, and sync plan updates.  It also adds the ability
to edit an individual product's sync plan on the product details page .

TODO
 - [x] Fix javascript error on sync on product page
 - [x] Fix create new sync plan
 - [x] Add missing javascript tests
 - [x] Add ruby tests
 - [x] Add server timezone to sync plan form
 - [x] Add remove sync plan action to product details page
 - [x] Add remove sync plan action to bulk product page
 - [x] Remove old sync schedules page and menu item
 - [x] Change sync scheduled message to something about being able to leave the page
 - [x] Fix link to sync management page from product details page
 - [x] Add breakdown of how many repositories failed, and how many succeeded instead of 'error'
 - [x] Add indication of next sync time for product and repository
 - [x] Display repository/product list for sync bulk actions
 - [x] Add new sync plan page to bulk actions