feat: restructure Starport commands

[fadeev]

Refer to the CLI "spec". Add scaffold, chain and other namespaces.

[ilgooz]

How to approach to the module create and module import commands?

a-Merge them into a single scaffold module command by probabbly introducing an --import flag?
b- Keep both sub commands under scaffold module namespace?
c- Change their names as scaffold module-create and scaffold module-import?

[fadeev]

Module scaffolding:

starport scaffold module foomodule

Properly importing modules becomes possible only after app.go is redesigned, so for now, temporarily:

starport scaffold wasm

[fadeev]

Once we have proper module installation, we'll introduce a module namespace:

starport module install
starport module search
starport module show
etc.

[lumtis]

Yeah I would personally put import out of scaffold since scaffolding is normally generating base code that is aimed to be then completed by the developer. While for import we just import the module, we don't except any customization from it