Add support for filtering EC2 instances in dynamic inventory

This allows filtering out EC2 instances based on various different
filters including tags. As requested in 7480 it supports logical "OR"
instead of "AND" on the provided list of filters.
Merge branch 'ec2-tag-filter' of https://github.com/michalgasek/ansible into michalgasek-ec2-tag-filter
Merge branch 'michalgasek-ec2-tag-filter' into devel