Move CoreAliasDialogModel classes.

Depends-On: I7ee9ec39fce785b8e374e50fd05f0ef824097ab0
Change-Id: I2905dd1596fad47d0c7beaa669331063b48bd305
Reviewed-on: http://gerrit.dmdirc.com/3588
Automatic-Compile: DMDirc Build Manager
Reviewed-by: Chris Smith <chris@dmdirc.com>