Replace CommandLineParser with something that support commands composition #14
Description
Currently CommandLineParser library is used to parse input of CLI tools. Unfortunately, this parser does not provide support of nested command/verbs, similar to what can be observed in docker or dotnet.
As a result, flow needs to be shipped as huge bundle of "independent" CLI apps, which makes deployments and usage a bit inconvinient.
Spectre.Console supports commands composition - that can be used to unify all flow functionality within one gateway.