Subtask of #1830588: [META] remove drupal_set_title()
Problem/Motivation
Using procedural drupal_set_title() inside controller class is not encouraged.
Proposed resolution
Replace drupal_set_title() with #title in page return array.
Remaining tasks
Issue patch
User interface changes
Refer parent issue at #1830588: [META] remove drupal_set_title()
API changes
Refer parent issue at #1830588: [META] remove drupal_set_title()