Introducing a new variable {{ROOTPAGENAME}}

Introduced a new variable ROOTPAGENAME which has similar
content like BASEPAGENAME.
ROOTPAGENAME only contains the name of the topmost page without namespace, e.g.
for "User:Name/Article/Subarticle" it should be "Name".
BASEPAGENAME would be "Name/Article" here.

Update : fixed indentation in maintenance/fuzz-tester.php

Added to RELEASE-NOTES-1.2.2

Bug: 6747
Change-Id: I71ef0a15c95c9145462f3aa7fdb3ed11dac79265
Merge "Introducing a new variable {{ROOTPAGENAME}}"