devlog #4 - NPC movement

Devlog article:

• https://boreec.github.io/posts/devlog-0004/

Features

• First enemy: the blob
• Skip turn on pressing spacebar
• Stone variation
• NPC movements (random and straight forward)

Fixes

• Actors cleanup
• Actors as non-walkable
• Change background color to black

Refactor

• Remove the MapNumber component
• Change the relationship between Actors and Map
• Move tile.rs, cellular_automaton.rs and noise.rs to the map plugin