get admin's accessible sections and return them as associative array ['section alias'=>'admin role']

Give admin permission to the newly created section
use AdminAuthorizerInterface, return section->alias instead of section->title
add alias getter in Role class
call alias get method instead of alias attribute
Merge branch 'develop' into fix/issue-7
remove personal environment configuration
Merge pull request #32 from Vinelab/fix/issue-7

Fix Issue 7