Silent Automated Install

The Windows client can be run with the options /SILENT or /VERYSILENT. These options can be used to automate installs and run unattended installations with deployment systems. The silent option will run the installer with the dialog shown and confirm all prompts. The very silent option will run the installer in the background without any visible windows or prompts.

Currently the installer kills all processes named Pritunl.exe to close the GUI application before updating it. This has the effect of also causing the installer to fork to a new process if the installer has the same Pritunl.exe name. When doing automated installs the installer filename should be renamed to avoid this issue.