[FEATURE] Shader API

**What feature would you like to be added.**
I would like to see RusherHack add the ability to work with different shaders (for example, main menu shaders)

**Is your feature request related to a problem? Please describe.**
No.

**Additional context**
An example of how it can be implemented in the API:

```java
RusherHackAPI.shaderManager.registerMainMenuShader(String shader)
```
