v0.9.6 - Skill management, switch system, intro presentation, exp based on mob level

FEATURE

- Implement skill management (database side)
- Implemented use case when player reaches 0 HP and dies
- Implemented countdown in login screen
- Created separate production database and test database
- Created "limbo" room, when you die or are disabled from gameplay you end up there
- Implemented video and photomontage of the introductory presentation of the game (Thanks to Mineos)
- Created marker that indicates which items are equipped
- Added foreground effects in scenes to make them more beautiful
- You can now see your equipped weapons and armor in the profile menu
- Implemented sword mouse cursor :) (Thanks to Mineos)
- Implemented the management of exp based on the level of the mobs, if you are stronger you get less experience, if you are weaker you get more experience
- Created switch system with requests to players via modal

FIX AND REFACTORING

- Fix green crystal graphic bug on player
- Graphic fix other player's attacks are now visible and also the animations
- Bug crashes everything if the user minimizes the browser
- Removed the ui skillspoints and stamina at the end of the battle
- Implemented the ability to unequip an item