Support command line arguments

[leesei]

So that I can invoke with this in command line:

simplest-file-renamer .

https://stackoverflow.com/questions/30815446/how-to-pass-command-line-argument-in-electron/37656760
https://stackoverflow.com/a/64613200/665507

https://discourse.appimage.org/t/command-line-parameter-transfer/1537/2
AppImage/AppImageKit#917

If time allows I'll create a PR 🤞.

[whyboris]

That's really cool! Thank you for the idea and I hope you open a PR 🤝

[leesei]

1.0.0 AppImage crashed on my Arch system, could be a change in system's gtk, see here
This encourages me to build from source and work on this idea.
First of all the 1.0.2 AppImage is working on my system.

The actual code is quite trivial:
leesei@e789ea8

Caveat:

• I only tested in AppImage on Linux.
  I don't know how to pass these parameters to npx electron . --serve, the process.argv.slice() offset is different.
• Only files are handled, directories are ignored like the UI's file dialog

[whyboris]

Really cool! Thank you!
I will try to find some time in the next month or two to try it out.
Meanwhile - please open a PR with your code change so I can merge it in once I test it on my side 🤝