Improve overall weapon system

[danilko]

As a player, I want to have more weapon to choose and better weapon switch system

Included but not limited to

• [ ] #18
• [x] #17
• [x] #27
• [ ] Better effects of overall system
• [ ] Small damage projectile weapon but reload faster
• [x] Implement effect for reducing all weapon loading time for a easy to debug behavior (such as able to purchase engine)

For UI

• [ ] Better UI to recognize current weapon status while not distract player
• [ ] Research and implement better user system

[danilko]

Also change overall projectile from raycast + area2D to pure Area2D again.

As it seem with godot 3.3.4, the Physics for Area2D are much more accurate alone.

This allows better performance for browser based export.