Improve handling of 'Manage Event' title

[mattwire]

Overview

Switch to using standard form method for assigning title so we have access to the title during postprocess.

Before

Title not set on form object during postprocess.

After

Title set on form object during postprocess and used in the "Saved" message:

Technical Details

Switch from CRM_Utils_System::setTitle() to $this->setTitle(). Assign the title to the form in CRM_Core_Form::setTitle() method as we've done with other extractions.

Comments

@alifrumin @lcdservices Either of you in a position to test from a UI POV?

[civibot]

(Standard links)

• If this is your first pull-request for CiviCRM, please browse CONTRIBUTING.md for information about the development and testing processes.
• If you are reviewing this pull-request, you may wish to consult the test sites and the Review Standards (long template, short template).

[alifrumin]

Hey @mattwire,

I took a spin of this on the jenkins build. It looks good to me.

Specifically I created a new event (which worked as expected)
On save of the new event, the 'saved' status message included the title of the event as described in the After section above.

[eileenmcnaughton]

Ok - this addresses the reviewer comments - merging