add unit tests for cmd mojito start
use mockery instead of call mojito start directly
modify tests basing on reviews feedback
supporting applicationConfigFiles definition in a setting other than master, specifically supporting runtime:common or runtime:server
Merge pull request #952 from caridy/app-json

supporting applicationConfigFiles definition in a setting other than master, specifically supporting runtime:common or runtime:server for that.
Merge pull request #946 from lzhan/clitests

add unit tests for cmd mojito start