Rethink placement of "Host parameter hierarchy" reference

[maximiliankolb]

the reference is currently only placed in the Provisioning hosts guide. We should evalute if it makes sense to add it to the appendix of all relevant guides.

https://docs.theforeman.org/nightly/Provisioning_Hosts/index-katello.html#Host_Parameter_Hierarchy_provisioning

original idea: #3288