Add zone dynamic and includes as service dependency

[Poil]

I propose these changes :

• Add the parameter "dynamic" to allow to not manage a zone if the file already exists
• Add as service dependencies the "includes" parameter

[aanriot]

Regarding the includes, I think that it has to be discussed on #104 as the formula becomes more and more cryptic on my own advice. Moreover, we have to ensure that it will not break existing support for RedHat (https://github.com/saltstack-formulas/bind-formula/blob/master/bind/files/redhat/named.conf).

Regarding dynamic zones, have you tried to declare such zones as pillars in configured_zones? It sounds a bit similar.

[javierbertoli]

@Poil did you have any time to check @aanriot 's comments? Also, perhaps using Salt's dynamic dns update makes sense for zones marked as dynamic, so we can add a state named dynamic.sls where we can manage records without breaking the zone's journal? (I mentioned this in the related issue #104)

[aanriot]

@Poil , were you able to check this PR again? Thanks.

[Poil]

Sorry I had no time, I will try in the next week to check if it is possible or not to include a subfile for record, but I think it is not possible.