Currently `sudo` is applied to `echo` resulting in:
`/etc/apt/sources.list.d/terraform.list: Permission denied`
Using `echo "..." | sudo tee /etc/apt/sources.list.d/terraform.list` fix the problem
- Removed usage of `apt-key` which is deprecated and replaced by `gpg` command
- Removed usage of `curl` command which is not present by default on Debian systems