Ignore a few more files to make working with the site a little easier (#352)

* Ignore active versions of Visual Studio Code per-project configuration files and `prettierrc` configuration.

* Added a template `prettierrc` and Visual Studio Code `tasks` file for those who want to use one.

* Added `extensions.json` to the `.gitignore`, too.

* Switched to a more generic exclude for the `.vscode` directory.

* Removed Prettier template.

* Removed the `template` file and associated line in `.gitignore`.

Author: daveverwer

.gitignore

@@ -18,3 +18,9 @@ xcuserdata
 
 # Build output
 .output
+
+# VS Code files
+.vscode
+
+# Prettier
+.prettierrc