Add basic cli tool to enable running on demand

[plastikfan]

Need to be able run jaxom adhoc. The basic cli tool needs to be able to read in and XML file and output the corresponding JSON. The tool needs the following parameters:

• file path to input xml file (positional: 1)

• xpath query (positional: 2)

• output file name (positional 3, optional) if missing display to screen

• [x] Read XML file and obtain the XML as string

branch: jaxom-cli

• [x] Set process code (process.exitCode = 1;)

[plastikfan]

Initial attempt at di/composition-root/cli startup is a bit off. After more consideration, we need the following:

• CommandLine: responsible for dealing with yargs, gets arguments via yargs.argv and provides an ICommandLineInputs instance.
• Injector: takes the command line inputs, using rules, creates the object graph from inputs and the dependency requirements between objects. Return the fully constructed application
• Application: the cli domain logic; invokes the converter

As it stands, the current commandLine and application logic needs to be swapped over for it to make sense. The composition root is a bit like a controller and invokes the commandLine => injector => application sequence. The index.ts invokes the composition root.

Also see: https://www.npmjs.com/package/di-ninja#21-composition-root

[plastikfan]

https://blog.developer.atlassian.com/scripting-with-node/#packaging-shell-commands https://developer.okta.com/blog/2019/06/18/command-line-app-with-nodejs

[plastikfan]

We need to build a separate bundle for the cli