feat: Added support for custom APT config and gpg key injection

[SkySingh04]

Add functionality to make the customAPTConfig and gpgKeys parameters optional in the installUpdates function of the dpkgManager struct. The function now checks if these parameters are provided before applying the custom APT configuration and adding the GPG keys.

• Conditional checks for customAPTConfig and gpgKeys in the installUpdates function.
• Update the function to apply configurations only if the parameters are provided.

Closes: #600