feat: build an image that uses runtime configuration

[kdmccormick]

Update: work is continued over here: overhangio#69

Description

• Add MFE_ENABLE_CONFIG_API as a boolean plugin setting.
• Add MFE_ENV_COMMON as a plugin setting.
  • This setting represents the config values that are shared across MFEs.
  • It contains "production" and "development" dictionaries.
  • The default values were taken directly from env/production and env/development.
  • Individual config values can still be overriden per-MFE by setting
    MFE_<APPNAME>_MFE_APP["env"].
• When MFE_ENABLE_CONFIG_API==True, use the new run-time config system:
  • In env/production and env/development, only render MFE_CONFIG_API_URL.
    • For production, set the MFE_CONFIG_API_URL=https://<mfe_hostname>/api/mfe_config/v1. Then, configure Caddy to forward this request to LMS. We must do this because the MFE does not know the LMS's base URL before it gets a response from the MFE Config API (thanks @ghassanmas for the idea).
    • For development, set MFE_CONFIG_API_URL=http://local.overhang.io:8000/api/mfe_config/v1. This is based on the assumption that LMS is always at local.overhang.io:8000 when using dev mode.
  • For each MFE, set the correct APP_ID in:
    • env/production.override, for production
    • dev/docker-compose.yml as an environment variable, for development
  • In the LMS's common.py settings file, render the contents of MFE_ENV_COMMON and MFE_<APPNAME>_MFE["env"] for the MFE Config API to serve.
• When MFE_ENABLE_CONFIG_API==False, use build-time config, just as tutor-mfe did before:
  • Render the contents of MFE_ENV_COMMON directly into env/production and env/development
  • Render the contents of MFE_<APPNAME>_MFE["env"] into:
    • env/production.override for production
    • dev/docker-compose.yml as environment variables, for development

To do

• Address "TODO" comments.
• Document newMFE_ENV_COMMON and MFE_ENABLE_CONFIG_API settings in the README.
• Test this thoroughly in dev, local, and k8s mode.
• Close this PR and re-open it against overhangio/tutor-mfe with a better commit message.
• Making the image automatically build and push to docker.io/overhangio/tutor-mfe

Links

• Closes https://github.com/overhangio/2u-tutor-adoption/issues/87

• Blocked by completion of: MFE runtime configuration openedx/wg-frontend#103, which requires merging:

  • feat: add mfe config api openedx/edx-platform#30473
  • feat: MFE configuration at runtime openedx/frontend-platform#335
  • feat: allow runtieme configuration openedx/frontend-app-profile#586
  • feat: allow runtime configuration openedx/frontend-app-learning#955
  • feat: allow runtime configuration openedx/frontend-app-account#603
  • feat: allow runtieme configuration openedx/frontend-app-gradebook#253

[kdmccormick]

closed in favor of #2