Feature: LDC-217 - made user permissions conditional

## Ready State: Yes

Relates to jira task:
https://imagex.atlassian.net/browse/LDC-217 

Allow permissions to be conditional by grouping them by module & then wrapping the group in module_exists calls.
This allows modules providing permissions to be turned off without making the feature overridden.

## Requirements & Dependencies

Requires PRs:
* https://github.com/imagex/imagex_patches/pull/44
* https://github.com/imagex/imagex_installkit/pull/82.

These contain patch to features module which allows this work to function.

## Deployment Instructions

* Merge code.
* Ensure imagex_user_permissions feature is enabled

## Usage/Test Instructions

* Run new build with drush make ensure the patch is applied cleanly
* Review imagex_user_permissions and find a permission it exports then disable the module providing the permissions and ensure the feature remains in a default state