docs: update README
docs: update README

BREAKING CHANGE: rewrite in functional style

`new Cli()` -> `createCli()`
`new PluginCli()` -> `createPluginCli()`

The types are retuned to support auto argument and options inference.
They are move under `Cli` and `PluginCli` namespaces to reduce noise during import.

unional/clibuilder,unional/clibuilder,unional/clibuilder