Add change view folder for VIew

I am sorry, but I do not see why the path should be changed during a request.

It is easy to add a setter if you extend the View class. 
I don't see why the setter should be provided to all CodeIgniter users.

The setter only complicates the View class and don't seem to have benefit.

ci-phpunit-test | CodeIgniter Testing Guide | CodeIgniter 3 to 4 Upgrade Helper