Add a javascript templates package

[joshuahannan]

Issue To Be Solved

We want to be able to release packages in other language so that apps written in those languages can import them to get the transaction code defined in the repo, similar to how it is done in Go.

Suggest A Solution

• Design and write a package in lib/javascript/ for getting template transactions.
• Use the templates in transactions/ and replace them with arguments that the caller provides.
• Write tests to make sure the templates are created correctly.