Add Dockerfile for e2e tests on mac

[mtsgrd]

Works with Tauri v2 - keeping as draft until #4789 has landed.

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[ndom91]

Pushed a small commit to merge some of the RUN commands to avoid creating new layers and cleaned up a few other things, hope thats alright :+1:

[ndom91]

@mtsgrd I added a small GHA for building and publishing this Dockerfile like we'd talked about. We'll still need to adapt the CMD / ENTRYPOINT and anything else? :thinking:

In a follow-up PR we can then update our test-e2e.yml webdriver job to use this image