Integration/smoke test

[vaind]

Similarly to the Unity SDK, we should run a (simple) smoke test to check a game builds with the Sentry plugin and errors are captured.
This should ideally happen in CI.

In order to do that for the currently supported plugin platforms, we would need macOS and Windows runners. Unfortunately, it looks like these are not readily available for use in CI and are supposed to be installed through the EpicGameLauncher in a non-automation-friendly way (a.k.a. clicking).

Therefore, to run this in CI, we have the following options:

• set up standalone macOS and Windows servers and install the appropriate versions manually + take care of server crashes, freezes, updates, etc
• try to avoid EpicGameLauncher, getting hold of the pre-built executable links and installing those in CI
• build the engine from source in CI - this requires about 90 GiB of free space on Windows, Engine v5.0.3
• build from source and get that to CI while complying with engine licences
• https://github.com/adamrehn/ue4-docker which provides Dockerfiles (we would need to make the built images private to comply with the Unreal EULA) for Linux and Windows.