Add initializers (analogous to finalizers)

[RafaelPalomar]

Is your feature request related to a problem? Please describe.
No

Describe the solution you'd like
I would like to have initializers. They could be like finalizers but happening before the package is installed. This could be useful to do system check

[mudler]

this is a good proposal, feel to take a stab at it?

[RafaelPalomar]

That would be my first ever go code...I promise to have a look when I get a little bit of bandwidth.