Added Baleroc Encounter

Implements everything from the Baleroc Encounter except for:

Vital Spark
http://www.wowhead.com/spell=99262

Vital Flame
http://www.wowhead.com/spell=99263

And the after-fight conversation initation for Majordomo Staghelm.
"Well well... I admire your tenacity. Baleroc stood guard over this keep
for a thousand mortal lifetimes. But NONE may enter the Firelord's
abode! Beg for mercy now, and I may yet allow you to live. Well,
‘heroes,’ what is your answer?"
GateIntro2: But none may enter the Firelord's abode
GateIntro3: Beg for mercy now, and I may yet allow you to live. Well
heroes, what is your answer?

This is my first real contribution to TrinityCore as a long-term world
of warcraft hardcore raider and I believe I can help TrinityCore on the
PvE side.

Apologies for any error I may have done uploading this, as it's my first
time using the GitHub client to submit a pull request as well.