feat: support icon and description in preset (#18977)

## Description 

This PR adds support for `description` and `icon` fields to
`template_version_presets`. These fields will allow displaying richer
information for presets in the UI, improving the user experience when
creating a workspace.
Both fields are optional, non-nullable, and default to empty strings.

## Changes

* Database migration with the addition of `description VARCHAR(128)` and
`icon VARCHAR(256)` columns to the `template_version_presets` table.
* Updated the `CreateWorkspacePageView` in the UI

Note: UI changes will be addressed in a separate PR

cli/testdata/coder_provisioner_list_--output_json.golden

@@ -7,7 +7,7 @@
     "last_seen_at": "====[timestamp]=====",
     "name": "test-daemon",
     "version": "v0.0.0-devel",
-    "api_version": "1.7",
+    "api_version": "1.8",
     "provisioners": [
       "echo"
     ],