Add support for Edxapp Extra Requirements

[iamjazzar]

Change description

Add support to EDXAPP_EXTRA_REQUIREMENTS. These requirements are used in production Ansible deployment scripts, but never were incorporated in the devstack.

@OmarIthawi introduced a way in our devstack (devstack#42) to install extra pip packages without modifying edx-platform. This PR introduces a new configuration variable (EDXAPP_EXTRA_REQUIREMENTS) that utilizes Omar's work, so it won't work on any devstack except Appsembler's, unfortunately.

The configuration variable expects a comma-separated list of pip packages git repos:

EDXAPP_EXTRA_REQUIREMENTS="https://github.com/appsembler/gestore.git==0.1.0-dev3,https://github.com/appsembler/course-access-groups.git"

To specify the version, simply add ==<branch_or_tag> after the repo link. If no version is specified, we will default to the main branch of the repo.

If the package you're installing is a Django app, then you might need to consider adding the app name to your ADDL_INSTALLED_APPS in your lms/cms YAML configs.

Note

This change is based on #76 (Hence first commit), so I won't be merging it until the PR is approved and merged.

Type of change

• Bug fix (fixes an issue)
• New feature (adds functionality)

Related PRs

• edx-platform#976
• edxapp-envs#4

Checklists

Development

• Lint rules pass locally
• Application changes have been tested thoroughly
• Automated tests covering modified code pass

Security

• Security impact of change has been considered
• Code follows company security practices and guidelines

Code review

• Pull request has a descriptive title and context useful to a reviewer. Screenshots or screencasts are attached as necessary
• "Ready for review" label attached and reviewers assigned
• Changes have been reviewed by at least one other contributor
• Pull request linked to task tracker where applicable