This change:
1. Reads location of airship config file from "airshipConfigPath"
key in airshipui.json
2. If key does not exist, it is added to airshipui.json along with
the default path of $HOME/.airship/config
3. If a user initializes or specifies a config file in a different
location, that location will be written to airshipui.json and will
be used in place of the default
Change-Id: I1d4282be26729427d14de8b60778a347f5e4f681
d053e593ac