Reorg : tf resource mapping as yaml file

[obierlaire]

In order to be able to add more providers and resource types more easily, we will be able to add internal/plan/mappings:

1. Add your provider name mapping in internal/plan/resources.go parseProvider(tfProviderName string)
2. Add a folder in internal/plan/mappings
3. In this folder, add a general.yaml (see other mapping examples)
4. In this folder add rest of mapping files
5. Add few tests

Mapping structure need to match internal/plan/mappingStructs.go