Update setup documentation to cover issue #1117

Fixes #2478

website: remove packer push var interpolation

This removes a message that is no longer accurate and fixed in https://github.com/mitchellh/packer/issues/1861

In issue #1117, the packer binary can sometimes conflict with the packer binary supplied with cracklib. This documentation update covers this and provides workarounds for affected users.

Fixes #2474:  Replace use of 'int' and 'uint' in website docs with 'integer' and wrap long lines

Add description of force option for docker-tag

Make manifest_file work as either file.pp or a directory

Fixes #2467 Add missing default values for 'disk_cache' and 'disk_discard' in qemu builder docs

Add missing default values for 'disk_cache' and 'disk_discard' in qemu builder docs, sort qemu_binary before qemuargs so it matches ordering from 'packer fix'

Add PTY to Docker exec

Added notes to warn against manifest_dir and note that manifest_file can be overloaded with a directory

Don't add ephemeral block devices to the EBS mapping

Merge branch 'documentation/ansible_inventory_groups' of https://github.com/Cbeck527/packer into b-ansible-inventory-docs

Fix inconsistent spelling

Use --portcount on VirtualBox 5.x