Open url based on OS

[agoodshort]

Everything is in the title, the plugin will now open URL based on the OS the user is on.

Tested on:

• OSX => no issues
• WSL Ubuntu => did not open the url (epected behaviour, potential fix in this situation)

Note:

• If you prefer, we could integrate the getOS.lua logic directly in http.lua

Credits:

• @Zbizu gist getOS.lua
• Commands to use per OS from this stackoverflow answer