Provide auto-update scripts for wide deployment

To ease the next and future wide upgrades of the Nuxeo Drive client,. we should provide deploy scripts.

One PowerShell script for Windows users and one Bash script for macOS users.

Script actions:

• kill eventual running Drive
• uninstall Drive 3.x, if installed
• uninstall any Drive < 4.4.0
• download the Drive 4.4.0 installer
• install Drive 4.4.0, if not already installed.

Those script will be kept inside the Nuxeo Drive repository on GitHub to centralize future modifications and ease versioning. Static URLs are:

• macOS: https://github.com/nuxeo/nuxeo-drive/blob/master/tools/osx/deploy-nuxeo-drive-mac.sh
• Windows: https://github.com/nuxeo/nuxeo-drive/blob/master/tools/windows/deploy-nuxeo-drive-windows.ps1

A link in the Nuxeo documentation will be added too.