Change smart contract template to not use "static" keyword for class data members and methods

[roschler]

Currently when you create a new smart contract the N3 template for the auto-generated C# contract has all the class data elements and methods declared as static. I spoke with DevHawk and this is no longer necessary with the newer compiler. If you create any non-static class elements you will not see the static elements in the drop-down list when you invoke the Intellisense auto-complete feature in Visual Studio Code, because they are in different scopes. Currently a user who wants to declare non-static elements must do a global search and replace operation on the boilerplate smart contract created by the plugin, to delete the static keyword. Please create a future version of the plugin that does not use the static keyword for the smart contract class elements, or at least provide a plugin setting to make it optional.