Vim syntax file for Kamailio 3.0

I updated the vim syntax file for Kamailio 3.0 and SR3.0/devel. There is now as well a script to auto-detect the type of .cfg file based on matching compatibility string (i.e., #!XYZ), loadmodule or main route line.

To install, copy the files in your home dir (see the hints inside each file to know which one to place where):

.vim/syntax/ser.vim

.vim/ftdetect/ser.vim

If you don't install the file type detect script, then you can use ":setf ser" once you opened the config file.