feat:add local task scoping for option() instead of global only mode

Currently option() works on global level (one singleton via an object).

While this behaviour might be ok for task or two, one will start having issue in bigger project.

To support good DX it should be able to locally scope option per task, which would have following outcomes:

• properly generate CLI flags when --help is invoked on particular task
• properly apply yargs parser on particular task

New Contrived API proposal

const { task, logger, option, argv } = require('just-task');

task('blimey', 'An exclamation of surprise.', function() {
  logger.info(`blimey! ${argv().name}`);
})
.option('name', {describe: 'user name or something'})


task('greet', 'say hi.', function() {
  logger.info(`say hi! ${argv().greeting} ${argv().who} !`);
})
.option('greeting', {describe: 'what greeting should be used'})
.option('who', {describe: 'who should we greet?'})

which would work like following:

just blimey --help

Options:
  --name    user name or something                                                 [string]
  --help     Show help                                                 [boolean]
  --version  Show version number                                       [boolean]

just greet --help

Options:
  --greeting    what greeting should be used                                                 [string]
  --who    who should we greet                                                 [string]
  --help     Show help                                                 [boolean]
  --version  Show version number                                       [boolean]

Start by tracing the task, option(), and argv() entry points and how the yargs parser currently obtains global options. Done means options can be scoped to an individual task, with task-specific --help flags and parsing matching the proposed blimey and greet examples.