Implement method to directly set volume of an application

[TheRedstoneDEV-DE]

What I did:

• added method to set volume of application directly
• removed Cargo.lock
• rewritten errors.rs, because of compilation errors

NOTICE

I am not a very experienced rust dev, feel free to give feedback if I did something incorrectly!

[TheRedstoneDEV-DE]

Sorry wrong repo!