add meta descriptions (#12315)

* add meta descriptions

* rework

* tweak

* clean up hcl description

* gt dash

website/content/guides/1.7-plugin-upgrade.mdx

@@ -1,5 +1,7 @@
 ---
 page_title: Upgrading your plugin to use the Packer plugin sdk
+description: >-
+  Learn how to upgrade your plugin to support v1.7.0 and later.
 ---
 
 # Upgrading your plugin to be compatible with Packer v1.7.0 and later

website/content/guides/1.7-template-upgrade.mdx

@@ -1,5 +1,7 @@
 ---
 page_title: Upgrading your template to use Packer init
+description: >-
+  Use packer init and the required_plugins block to better control plugin usage within Packer templates. Learn how to update your template to work with these new features.
 ---
 
 # Upgrading your template to be compatible with `packer init`

website/content/guides/hcl/index.mdx

@@ -1,5 +1,7 @@
 ---
 page_title: Getting started configuring Packer with HCL2 files
+description: >-
+  Use the HCL2 syntax for your Packer templates. Learn about arguments and blocks, comments, and multi-line strings.
 ---
 
 # Introduction to Packer HCL2

website/content/guides/packer-on-cicd/build-image-in-cicd.mdx

@@ -1,5 +1,7 @@
 ---
 page_title: Build Images in CI/CD
+description: >-
+  Learn how to build Packer images within a continuous integration / continuous delivery pipeline.
 ---
 
 # Build Images in CI/CD

website/content/guides/packer-on-cicd/build-virtualbox-image.mdx

@@ -1,5 +1,7 @@
 ---
 page_title: Build a VirtualBox Image with Packer in TeamCity
+description: >-
+  Use Packer to build VirtualBox images in TeamCity. Learn how to provision a bare-metal machine, install dependencies, and create and run a build in TeamCity.
 ---
 
 # Build a VirtualBox Image with Packer in TeamCity

website/content/guides/packer-on-cicd/index.mdx

@@ -1,5 +1,7 @@
 ---
 page_title: Build Immutable Infrastructure with Packer in CI/CD
+description: >-
+  Learn how to use Packer to build immutable infrastructure within a continuous integration / continuous delivery pipeline.
 ---
 
 # Build Immutable Infrastructure with Packer in CI/CD

website/content/guides/packer-on-cicd/pipelineing-builds.mdx

@@ -1,8 +1,7 @@
 ---
 page_title: Packer Build Pipelines
-description: |-
-  Here we explore how to break your builds into discrete steps so that your
-  builds can be shorter and more reliable.
+description: >-
+  Learn how to shorten Packer build times and improve reliability. Start from an ISO, customize using the virtualbox-ovf builder, and improve efficiency.
 ---
 
 # Why Create a Template Pipeline?

website/content/guides/packer-on-cicd/trigger-tfe.mdx

@@ -1,5 +1,7 @@
 ---
 page_title: Trigger Terraform Enterprise runs
+description: >-
+  Learn how to Terraform Enterprise from your CI/CD pipeline to provision infrastructure.
 ---
 
 # Create Terraform Enterprise Runs

website/content/guides/packer-on-cicd/upload-images-to-artifact.mdx

@@ -1,5 +1,7 @@
 ---
 page_title: Upload VirtualBox Image to S3
+description: >-
+  Learn how to upload a VirtualBox image built with Packer to S3 within a TeamCity build.
 ---
 
 # Upload VirtualBox Image to S3