More enemies and progress on the warehouse level

Added two new enemy types - a fixed turret as well as a giant, moving spider robot, and a nice effect where the latter crashes through the wall at an unexpected time.

Using unreal engine 5's chaos physics, the fields plugin, and controlling enemy path finding a bit by blocking out the edges of the destructible wall, finally led to the intended effect.

It was also time to start moving away from the blocky, overly simplified level layout in the warehouse level. As can be seen in the screenshot, some textures have changed, and a number of beams have been added to make the warehouse look more realistic - but it's not yet finalized. A few new rooms were also added. In the next update, I hope to have more or less finished the warehouse level in its first draft form, and after that begins fine tuning and tweaking all little details to make for the best possible playing experience.