Create & Template Experience Enhancements

[ntotten]

This issue is a summary of several related issues that deal with the templating and create experience in the CLI and VS Code.

There are several issues with the current templating experience in the CLI and Visual Studio Code that should be addressed. They are:

1. There is a fairly small set of templates to choose from. Other tools and IDEs offer a much more extensive set of templates when creating projects and files.
2. The templates are not customizable. It is common for developers and organizations to have their own styles and patterns for templates. Currently, there is a single template set that lives in the source of the CLI.
3. The process of creating various templates is rigid. Neither the CLI, nor VS Code prompts for many customization options when creating various templates.
4. The process of creating templates is not standard. Different types of templates require different options (i.e. directory selection, etc.)
5. Template creation UI in VS Code is either difficult to find or appears in the wrong places.
6. Template creation is slow - the CLI and VS Code take 5+ seconds to create various templates.

The proposed solution is to rebuild the templating experience to accommodate solutions to the above problems.

The following issues offer proposed solutions: #702, #705, #784, #471, #852, #606

[ntotten]

See: forcedotcom/salesforcedx-templates#98