Add ability to create a file template

[pheg-mural]

Would be great if you could set file template, like in this extension: https://marketplace.visualstudio.com/items?itemName=hardikmodha.create-tests

I like your extension because it provides better test file creation regex AND the goto/gofrom test file is amazing.

  "createATestFile.testFileTemplate": [
       "import { ${moduleName} } from '${modulePath}';"
    "",
    "describe('${moduleName}', () => {",
    "\tit('', () => {",
    "",
    "\t})",
    "})"
  ]