Since cloud-init templates may vary from one release to another,
fuel-agent should be able to choose appropriate version according to
environment version provided in provision data.
Due to matter of changes, only boothook templates were affected,
the rest of templates haven't been changed yet.
* add templates from 6.1/stable
* add templates from 7.0/stable
* rename meta-data to meta_data
Change-Id: I03f9c304edb387435747c5f59d83516e8adcce9f
Closes-Bug: #1478549
Depends-On: I81b50863a58de10ee33c8064b38fc92ef7e1d86a
4352af292b