Reorganize Parser class

Extract helper methods from the `initialize` method of this class to
make it easier to understand.

Change-Id: Ic2fea460522dfad1d8c45887f48a9a51d1675691
Reviewed-on: http://gerrit.causes.com/44717
Tested-by: jenkins <jenkins@brigade.com>
Reviewed-by: Shane da Silva <shane.dasilva@brigade.com>