Add room DAG visualizations

Nobody has claimed this yet.

During monthly wrap-up demos today, I heard that @jryans had plans to add the room DAG visualization to the [`patience` test harness](https://github.com/matrix-org/collaborative-documents/tree/main/test/patience) interface 😍 This is exactly what I have been aspiring to add as well!

> Would be cool to make a generalized solution to make a TARDIS visualization for any test run in Complement (after hook to save a file which we can view in TARDIS)
>
> *-- https://github.com/matrix-org/complement/pull/68*

Patience already automates hooking up Element to the homeserver which I was doing manually and added docs for, https://github.com/matrix-org/complement/blob/master/ONBOARDING.md#how-do-i-hook-up-a-matrix-client-like-element-to-the-homeservers-spun-up-by-complement-after-a-test-runs

So it sounds like a perfect opportunity to combine some efforts 🤠. My use case is a little different as I am after testing the homeserver vs testing a client but there is so much overlap here.

For reference on the DAG visualizations I have been generating so far, I adapted TARDIS to work with Synapse, https://github.com/matrix-org/tardis/pull/1


Start by reading the test/patience harness interface and the referenced Complement PR 68, then compare the Synapse adaptation in TARDIS. Define how a test run exposes its room DAG and how the generated file is opened in TARDIS; done means the patience harness can produce a visualization for the relevant test runs.

Written by the indexing model from the issue text.