refactor: folder structure

internal/cmd/bulk.go

internal/cmd/group.go

internal/cmd/group/create.go

internal/cmd/group/delete.go

internal/cmd/root.go

internal/cmd/user.go

internal/cmd/user/block.go

internal/cmd/user/create.go

internal/cmd/user/group.go

internal/cmd/user/mod.go

internal/cmd/user/remove.go

internal/cmd/user/reset.go

internal/cmd/user/show.go

internal/cmd/user/temp.go

internal/cmd/user/unblock.go

main.go