Core/Misc: Refactor scripts to fix static analysis warnings

Seventh batch of fixes targeting 100 issues reported by Coverity
Scripts/Examples: Remove outdated example scripts

Remove outdated misleading example scripts not following anymore current TC codestyle and standards. Please refer to the wiki or forum for up to date examples and documentation.
Core/Players/DK: Implement Rune Grace Period mechanic

Closes #11736
Fixes #6122
Scripts/Examples: Remove some more code related to example scripts
Core/Spell - Fix Remove Aura "The Eye of Acherus"

Fixed remove aura "The Eye of Acherus" http://www.wowhead.com/spell=51852 after use "Recall Eye of Acherus" http://www.wowhead.com/spell=52694 .
Earlier, after using the player remained under the aura.