Revert "roles/nginx: Ingenius use of YAML hashes to derive TLS key from another file"

This reverts commit 59b9bd70b8055d4274044bef4f9aef6d41367144.

Might not be so ingenious.  Can't get this to work anymore...
host_vars/web05: Add TLS keys back

The other method wasn't as clever as I had thought, as I couldn't
get it to work again!

Signed-off-by: Alan Orth <alan.orth@gmail.com>