Feature: LDC-438 Set default, add "admin" user to workbench sections

## Ready State: Yes

#### JIRA Reference: https://imagex.atlassian.net/browse/LDC-438

Set default, add "admin" user to workbench sections

## Deployment Instructions

* Merge code.
* Clear caches with `drush cache-clear all`

## Usage/Test Instructions

* Reinstall profile or `drush dis imagex_workflow -y`, `drush en imagex_workflow -y`
* Browse to `admin/config/workbench/access/editors/taxonomy/workbench_section`