Add generator add command to Marketplace generator

Description

See section Changes need to the Marketplace CLI of the spec

QA Test Steps

No testing required.

Reporter

None

Status

Mana

4

Assignee

Ben Schumacher

QA Assignee

Prapti Shrestha

Reporter

Ben Schumacher

Epic Link

Fix versions

Mattermost Team

Toolkit

Sprint

None

Labels

None

QA Testing Areas

None

GitHub Issue

None

Components

Configure