Allow passing "copyright" config to DEB and RPM makers

[p2kmgcl]

Pre-flight checklist

• I have read the contribution documentation for this project.
• I agree to follow the code of conduct that this project uses.
• I have searched the issue tracker for a feature request that matches the one I want to file, without success.

Problem description

It looks like electron forge is not passing "copyright" options to DEB and RPM makes, the result is that any application will have the "Electron Github" copyright in the documentation of the package (grep '^' /usr/share/doc/my-electron-app/copyright).

Proposed solution

Both redhat and debian installers already support this parameter, we only need to pass that information to them:

• https://github.com/electron-userland/electron-installer-redhat/blob/main/src/installer.js#L30
• https://github.com/electron-userland/electron-installer-debian/blob/main/src/installer.js#L41
• https://github.com/electron-userland/electron-installer-common/blob/master/src/installer.js#L174

Alternatives considered

We've considered patching the deb/rpm packages after building them, but I would like to avoid manipulating the binaries generated by electron forge.

Additional information

No response