JU-6: add support for openedx-filters

[mariajgrimaldi]

Description

This PR adds support for Open edX Filters in Limonero. These filters are part of the OEP-50: Hooks Extension Framework implementation plan.

For an overall understanding of the design, check out the Open edX Filters ADRs and discussions:

1. Open edX Filters naming and versioning ADR
2. Open edX Filters Payload Conventions ADR
3. Open edX Filters tooling
4. Other Docs

Supporting information

Discuss on Hooks Extension Framework:
https://discuss.openedx.org/t/configuration-for-the-hooks-extension-framework/4527/
https://discuss.openedx.org/t/hooks-framework-filters/5753

Testing instructions

1. Checkout to li/ednx/JU-6_P3
2. Install Open edX Filters library: pip install openedx-filters
3. Connect your custom actions to the filter (in your site settings):

    "OPEN_EDX_FILTERS_CONFIG": {
        "org.openedx.learning.course.enrollment.started.v1": {
            "fail_silently": false,
            "pipeline": [
                "eox_taylor.XXXX.XXXXX.actions.CanPerformEnrollmentByTag"
            ]
        }
    }

5. In your course advanced settings, add:

{
    "tags": ["premium"]
}

6. Install eox-taylor: pip install git+https://bitbucket.org/edunext/eox-taylor/eox-taylor.git@li/ednx/JU-6_P2 #egg=eox-taylor==2__1

7. Now try to enroll: