Use jinja macros to access the pillar data

[ricardoasmarques]

There is a lot of duplicate code to fetch data from the pillar, especially due to all the handling of non-existent keys in the pillar.

The objective is to create some jinja macros that can be used to reduce the amount of duplicate code.

See https://jinja.palletsprojects.com/en/2.10.x/templates/#macros