Automate "installation" of the starter kit

[SeanTAllen]

At the moment, the "installation" of the starter kit is very manual. Ideally, what we want is:

A script that can be run that will prompted the user for:

• all required values
• target location to install files

the script will then run and copy over all files from this repo (other than USAGE.md and other "support" files) while replacing the templated values. Additionally, it would create the "{PACKAGE}" directory and install a stub _test.pony file with contents such as:

use "ponytest"

actor Main is TestList
  new create(env: Env) =>
    PonyTest(env, this)

  new make() =>
    None

  fun tag tests(test: PonyTest) =>
    None

Before you start on this issue, ping me where to discuss the proper tooling for doing template replacement and installation.

Ideally, we want to use tool(s) that are ubiquitous such that most people will have them installed (across macOS, Linux, and Windows if possible). Getting all 3 though seems difficult. We might need something for macOS and Linux and then another for Windows.

[SeanTAllen]

Step 1 of this, that I would undertake is using sed to make replacements in Unix environments. However the current "template" scheme that I've done of {VARIABLE} conflicts with ${Foo} from bash, so {VARIABLE} will need to be changed before any autogeneration work can be done.