[Hyper-cli] Add cli cmd

[chabou]

Replace #2337

DO NOT MERGE IT. This feature was created to make review easier.
This PR is already merged in #2375 branch (the only one that should be merged).

• Hyper CLI javascript file is bootstrapped by scripts (located in build/(mac|win|linux)/)
• Right platform script(s) are copied at build time to resources/bin/
• When installing Hyper on Linux, platform script is symlinked to /usr/local/bin.
• At Hyper startup time (only in production mode), platform script is symlinked to /usr/local/bin on Mac, or resources/bin is added to user PATH env var on Windows.

[chabou]

There is a caveat with Windows.

I correctly add hyper bin path to user path. But there is some cache mechanism. User should go to "Modify user env var" dialog and just hit ok button (or reboot his computer )

[chabou]

There is an error on Linux

Failed to symlink Hyper CLI { Error: EACCES: permission denied, unlink '/usr/local/bin/hyper'
  errno: -13,
  code: 'EACCES',
  syscall: 'unlink',
  path: '/usr/local/bin/hyper' }

parallels@ubuntu:~/hyper$ ls -lah /usr/local/bin/
total 8.0K
drwxr-xr-x  2 root root 4.0K Oct 23 00:02 .
drwxr-xr-x 10 root root 4.0K Jul 19  2016 ..
lrwxrwxrwx  1 root root   16 Oct 23 00:02 hyper -> /opt/Hyper/hyper

I don't think that electron-builder can execute postinstall scripts.

I don't know how to resolve this.
Possible workaround:

• rename Hyper CLI command to hyper-cli or hpm or hyperctl
• Embed CLI handling directly in Hyper (but deal with unique app instance restriction)

Any thought @rauchg @leo @Qix- @albinekb @CodeTheory @Stanzilla @derrickpelletier ?

[Stanzilla]

I kinda liked hpm, my other idea was more of a joke but we could use a unicode symbol in the app name 😸

[chabou]

I was wrong! I found how to execute postinstall script with electron-builder 🎉 🎉 🎉
See afterInstall option.

[chabou]

Merged with #2375