share st-lutherx theme with edx-platform themes

[zubair-arbi]

For overriding the react js files we need to put our custom theme st-lutherx inside the edx-platform / themes / st-lutherx.

For dev environment, devops have updated the configuration to copy the themes in the edly-edx-themes in the edx-platform / themes / st-lutherx to make the custom react js files work.

---

For devstack we have a workaround to create an empty folder st-lutherx inside the edx-platform / themes the stop and up the devstack (with current changes), this will mount / sync the st-lutherx theme ../src/edly-edx-themes/st-lutherx with the empty folder st-lutherx inside the edx-platform / themes.

---

Also created an new docker make command stop-extra to stop the extra containers which we don't need for Edly development environment.

make stop
make dev.up
make stop-extra

---

Compiling the st-lutherx themes:

1. Assuming we are in devstack repo in bash, go to LMS shell inside the docker LMS container by running command "make lms-shell"
2. Open the environment configuration file "lms.env.json" by running command "nano ../lms.env.json"
3. Enable comprehensive themes functionality by setting the flag "ENABLE_COMPREHENSIVE_THEMING" to "true"
4. Provide comprehensive themes directory by providing the path "/edx/app/edxapp/edx-platform/themes" in the config var "COMPREHENSIVE_THEME_DIRS"

Note 1: Make sure now you have only one path /edx/app/edxapp/edx-platform/themes in the config var "COMPREHENSIVE_THEME_DIRS" otherwise if we dont follow this step then we will get errors like ReactRenderer module not found etc

Note 2: Please take a backup of your ../lms.env.json before stopping and starting the devstack as the changes in ../lms.env.json lost on devstack restart

[zubair-arbi]

@ziafazal please review this change, with this change we will mount the st-lutherx theme inside the edx-platform/themes to resolve our directory context issue for overriding react js files.