Review enemy prefabs (colliders, navmeshes).

[kazusaki1]

Ensure that existing enemy prefabs have all its components, and check if such components are well placed. This issue will be adressed on the same branch as #238 to avoid bloating the repository with branches and pull requests.

Definition of Done:

• [x] Fix enemy-porky texture
• [x] Fix enemy-porky navmesh agent
• [x] Fix enemy-porky collider
• [x] All enemy rigid bodies set as kinematic
• [x] All enemy rigid bodies without gravity
• [x] All enemy prefabs have their components placed correctly

Branch: dev_enemies

Estimation of time: 1 hour

Pull request: #295

[sdiaz7]

Issue ready for review. Waiting for #238

[sdiaz7]

Branch merged into DEV. Issue closed and moved to DONE.