Migration work to new Terraform schemas (WIP)
Fixes configuration

Newer Terraform versions use HCL, its parser is relatively new and have
some glitches. One of them is not being able to report the correct line
and column when a value that was supposed to be a string is not enclosed
with double quotes.
Doesn't seem we need TypeSets but TypeList
Fixes some plugin crashes
Network adapters are attached correctly again.
Merge pull request #20 from cloudescape/new-schema-work

Migrates plugin to new Terraform plugin framework