Add VuMark database support

[adamtheturtle]

Summary

Add support for creating VuMark databases and uploading VuMark SVG templates through the Vuforia Target Manager web UI.

Motivation

The VuMark Generation API endpoint was added to vws-python-mock (#473), but the tests currently use mock_only_vuforia because real Vuforia returns 422 InvalidTargetType — the CI test databases contain regular image targets, not VuMark targets.

VuMark targets can only be created through the Vuforia Target Manager web UI, not through the VWS REST API. Since vws-web-tools already automates this web UI for creating regular cloud databases (used by admin/create_secrets_files.py in vws-python-mock to provision CI test databases), it is the natural place to add VuMark database support.

Proposed Changes

1. Create VuMark database — Modify create_database() or add a new function to support selecting the "VuMark" database type instead of "cloud" in the Target Manager UI.

2. Upload VuMark SVG template — Add a function to upload an SVG VuMark template file to a VuMark database via the "Add Target" flow in Target Manager.

Follow-up

Once this is implemented, vws-python-mock can update admin/create_secrets_files.py to provision VuMark databases alongside regular databases, enabling VuMark generation tests to run against real Vuforia with verify_mock_vuforia.