Expose variables to JavaScript when viewing details or examining a log

When examining AbuseFilter logs using user scripts, it is convenient to have
access to the variables shown in the table, without having to interact with
the page to get the content of the table cells.

This change introduces the variable wgAbuseFilterVariables on these pages:
* Special:AbuseFilter/examine
* Special:AbuseLog/<logId>

Change-Id: I2cebf141e6c1d26e62ed7e6ba0b5c327694e2ef8