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

coderd/provisionerdserver/provisionerdserver.go

@@ -2264,6 +2264,7 @@ func InsertWorkspacePresetAndParameters(ctx context.Context, db database.Store,
 				prebuildSchedules = protoPreset.Prebuild.Scheduling.Schedule
 			}
 		}
+
 		dbPreset, err := tx.InsertPreset(ctx, database.InsertPresetParams{
 			ID:                  uuid.New(),
 			TemplateVersionID:   templateVersionID,
@@ -2273,6 +2274,8 @@ func InsertWorkspacePresetAndParameters(ctx context.Context, db database.Store,
 			InvalidateAfterSecs: ttl,
 			SchedulingTimezone:  schedulingTimezone,
 			IsDefault:           protoPreset.GetDefault(),
+			Description:         protoPreset.Description,
+			Icon:                protoPreset.Icon,
 		})
 		if err != nil {
 			return xerrors.Errorf("insert preset: %w", err)