[BB-4023] Create MicroSite Configuration on different services

Description

This PR adds a set of scripts to generate microsite-related configurations for LMS, discovery, and ecommerce services from a given configuration file.

Supporting information

https://tasks.opencraft.com/browse/BB-4023

Testing instructions

1. Pull this PR to src directory of your local devstack
2. Copy config/sample.yaml to config/config.yaml
3. To generate & test LMS configurations -
   • Login to LMS shell - make lms-shell
   • Go to microsite directory - cd /edx/src/microsite-generator
   • Run - make dev.run-lms
   • Check if Site, SiteConfigurations, Organizations has been created from LMS admin.
4. To generate & test Discovery configurations -
   • Login to Discovery shell - make discovery-shell
   • Go to microsite directory - cd /edx/src/microsite-generator
   • Run - make dev.run-discovery
   • Check if Site, Partner has been created from Discovery admin.
5. To generate & test eCommerce configurations -
   • Login to eCommerce shell - make ecommerce-shell
   • Go to microsite directory - cd /edx/src/microsite-generator
   • Run - make dev.run-ecommerce
   • Check if Site, Partner, SiteConfiguration has been created from eCommerce admin.
6. Check features in README.md of this PR, and play with the config/config.yaml to test other features.

Deadline

ASAP

Other information