feat: add options.binName

[fcastilloec]

I've been playing with the idea of switching to using reverse DNS for the name of my apps. When using any of the installers based on this module, if I set options.name to a reverse-DNS name, this also affects the symlink created by it.
This might not always be the preferred behavior, so perhaps introducing a new option to set the name of the binary symlink might be a good idea.
The new option defaults to the same values as options.name, so this shouldn't break anything. We will have to update desktop.ejs for -debian and -redhat (perhaps other modules too?) to use the new option in the Exec= field.

Currently, I've named it binName but I'm not set on the name, other ideas could be: symlink, symlinkName, or binarySymlink

[codecov]

Codecov Report

Merging #78 into master will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master       #78   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           13        13           
  Lines          210       210           
=========================================
  Hits           210       210           

Impacted Files	Coverage Δ
src/defaults.js	100.00% <ø> (ø)
src/installer.js	100.00% <100.00%> (ø)

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