WL#2393: Refactor Windows service installation and startup

The service installation and startup on Windows is implemented by a custom main() 
function in sql/mysqld.cc that does magical things based on the number of 
arguments given to the mysqld.exe program. This results in some strange behavior 
when starting up mysqld.exe with just a few arguments, an arbitrary limitation 
that the --install and --remove arguments appear first, and an arbitrary 
limitation of only one command-line argument being specified for the installed 
service.

This is unnecessary, and it should be possible to simply integrate the service 
startup and installation into the normal main() routine by adding handling for the 
"--install" and "--remove" switches, and an understanding of the single service-
name argument that is passed during service startup.