Boss update

We have been working in the idea that we talked some devlogs ago.

What we have now is:

• All the movement related to the minions and their links with the boss.
  
• Enemies die when you cut through it's link with the boss.
  
• Enemies trigger a bullet explosion on death (for now, leaving a single bullet)

This can be seen in the following gif

The only feature pending is adding the asteroids that block your way.

Aside from features we want to add. We would also want to change the current logic of the links, migrating them to Raycast2D nodes, since they work exactly for what we want to do (because currently you can cut an enemy's link crashing it in any point).

Also changing the current assets for the boss and the minions is a must. We just haven't decided what to replace them for.

This is all we can update for now, this last part has been kinda tricky because the boss mixes various techniques and concepts regarding game development and physics.