[Feature] Add Support for DrawIO embed parameter

Feature Description

Support for passing through the embed=1 parameter to the embedded DrawIO instance and passing its responses back. Parameter documented here: https://www.drawio.com/doc/faq/supported-url-parameters

Problem Context

Rather than plain DrawIO, I am trying to embed this tool as the DrawIO URL in a BookStack container.

Proposed Solution

Support the ?embed=1 parameter in URLs for this tool, correctly passing it to DrawIO and passing the DrawIO responses back to the original page.