Update documentation for PuppetDB 1.2.0
(cherry picked from commit 22238652b8a66e1c8b890e0de47a080d9a09a19a)
Remove references to Puppet Enterprise which isn't supported

This only removes references regarding installation/upgrade on PE.
Bits about maintaining or interacting with PuppetDB are included, since
that still applies.
(cherry picked from commit c9b6b3e47f4581fbb51fe19724123d1a22d5457d)
Fix dangling colon in docs
(cherry picked from commit 3d3e705c398d48e8695518f75e62a14e13981e05)
Clarify wording about PE and PuppetDB 1.2
(cherry picked from commit c9d187c6ac783c21be0d83b6dbbbe4850f255b6a)
Further wordsmith PE support
(cherry picked from commit 5aacab3304701c115787dd012e43ea3cdd1e1029)
Create incoming dir *before* we need it in deb packaging

During the packaging rework, this code was rearranged a bit, such that
it was using the incoming dir before creating it.
(cherry picked from commit 3ad72127bd63ff3224ba5e324b62db1a8313808f)
Docs: Be clearer about which users should use which installation path

It was brought to our attention that PuppetDB is sometimes installed by people
who don't already know how to use Puppet -- these people should probably go with
the packages instead of the module.
(cherry picked from commit 798846e3a5d2207699ebfac83998b1075ee34b89)
Merge pull request #490 from kbarber/maint/master/missing_cherries_from_12x

Maint/master/missing cherries from 12x