Terraform support for UpCloud (#7360)

* terraform support for UpCloud

* terraform support for UpCloud

* terraform support for UpCloud

* terraform support for UpCloud

* terraform support for UpCloud

* terraform support for UpCloud

* terraform support for UpCloud

* Updates to README.md and main.tf files

* formatting and updating readme

* added a .terraform_validate CI job

* fixed format issue

* added sample inventory

* added symbolic link to group_vars

* added missing tf variables and minor fixes

* added text formatting

* minor formatting fixes