I found template files in “[Unity-installation-folder]\Editor\Data\Resources\ScriptTemplates” and edited 81-C# Script-NewBehaviourScript.cs.txt file as I wish (Note: Use for example Notepad++ as administrator for editing).
Now I want to add Current Date, Developer Name, Project Name and other project corresponding data by default. Can someone post full list of available Key Vars (like we have now #SCRIPTNAME#)?
looks like there are only a few, and none that you’re looking for 
“#NAME#” - filename without extension
“#SCRIPTNAME#” - as defined
“#SCRIPTNAME_LOWER#” - looks like it’ll use the script name, starting with a lower case letter.
for what you’re after, you’re better off writing your own. it’s relatively straightforwrad - there are many editor script tutorials. or maybe some kind soul has posted on the wiki/asset store.
EDIT: i forget about this:
i made some mods to it a long time ago, if you’re interested i’ll try to dig it out.