Add starting game entities using DSL

[xsebek]

Is your feature request related to a problem? Please describe.

We shift the base to greener pastures, but that makes everything more complicated and the DSL less powerful. I want base to stay at the zero.

Describe the solution you'd like

Use world DSL to add whatever we need somewhere in the vicinity of base.

• Observe that base does not shift then.
• Move the shifting code to unit tests.
• Make the world a simpler and happier place ™️.

Describe alternatives you've considered

We could get the base shift in DSL and then continue adding things.

Additional context

This should enable adding burned terrain around base using the DSL.

[byorgey]

Related: #242 #1889