Define value mappings in the provider variables

[anmoel]

Is your feature request related to a problem? Please describe.
Define value mappings in the provider variables so that abbreviations for object types can be managed centrally

Describe the solution you'd like

provider "convention" {
  definition = "(region)-(name)"
  variables = [
    {
      name        = "region"
      default      = "europe-west1"
      mappings = {
        "europe-west1"  = "ew1"
        "europe-west4" = "ew4"
        "us-east1"         = "ue4"
      }
    }
}

resource "convention_name" "sql" {
  name = "one"
  inputs = {
    "region" = "europe-west4"
  }
}

result: ew4-one