feat: add set custom primary colors method in initialize flow

[andrey-canon]

Description:

This allows to set the primary colors based on the setting CUSTOM_PRIMARY_COLORS.

Issue # 1454
This is a migration pr of #11

How to test

1. You need a functional verawood MFE in your local machine. This instructions consider frontend-app-learning branch (open-release/verawood.nelp)
2. Add the module.config.js file into the frontend-app-learning folder, The frontend-platform project must be accessible from the mfe tutor container

module.exports = {
    localModules: [
        { moduleName: '@edx/frontend-platform', dir: '../frontend-platform', dist: 'src' },
    ],
};

3. Checkout this branch
4. Ad the following setting to the MFE_CONFIG(env/apss/openedx/settings/lms/development.py)

MFE_CONFIG["CUSTOM_PRIMARY_COLORS"] = {
    "pgn-color-primary-base": "#00AA00",
}

Expected result

[johanseto]

LGTM working in my local env.