Remove platform and platform version from package names

Specifically, el, freebsd, windows, and other; ubuntu has been addressed already in #88.

cc @opscode/release-engineers 
So right now the `iteration` is somewhat magic in that it includes things like platform versions and architecture on certain platform families. We need to change it to simply return the `build_iteration`. It might be best to also deprecate the `iteration` method and recommend calling `build_iteration` directly. The actual package naming logic resides down in the [output_package](https://github.com/opscode/omnibus-ruby/blob/v3.1.1/lib/omnibus/project.rb#L721-L748) method. This method needs to be updated to remove any references to platform and platform version and include architecture where appropriate. I'll try to explain what "as appropriate" means. We do both 32 and 64-bit builds for a number of platforms. These include:

* Debian
* EL
* Ubuntu
* FreeBSD
* Solaris
* AIX

FPM adds the architecture to the final package name for DEBs and RPMs so that means we really only need to append the architecture on the following platforms:

* FreeBSD (makeself / .sh)
* Solaris (pkgmk / .solaris)
* AIX (AIX backup format / .bff)