docs: added page about installing Terraform

docs/source/prod-node-setup-mgmt/install-terraform.md

@@ -0,0 +1,25 @@
+# Install Terraform
+
+The [Terraform documentation has installation instructions](https://www.terraform.io/intro/getting-started/install.html) for all common operating systems.
+
+## Ubuntu Installation Tips
+
+If you want to install Terraform on Ubuntu, first [download the .zip file](https://www.terraform.io/downloads.html). Then install it in `/opt`:
+```text
+sudo mkdir -p /opt/terraform
+sudo unzip path/to/zip-file.zip -d /opt/terraform
+```
+
+Why install it in `/opt`? See [the answers at Ask Ubuntu](https://askubuntu.com/questions/1148/what-is-the-best-place-to-install-user-apps).
+
+Next, add `/opt/terraform` to your path. If you use bash for your shell, then you could add this line to `~/.bashrc`:
+```text
+export PATH="/opt/terraform:$PATH"
+```
+
+After doing that, relaunch your shell or force it to read `~/.bashrc` again, e.g. by doing `source ~/.bashrc`. You can verify that terraform is installed and in your path by doing:
+```text
+terraform --version
+```
+
+It should say the current version of Terraform.