feat(redwood): update templates to support redwood release

[dcoa]

This PR updates the templates according to the upstream redwood release.

Changes

1. lms/main.html: Provides a fallback for gettext functions in the development environment
2. lms/coursewere/courses.html: filter courses by user language by default
3. cms/header.html: Add conditional to display help button in no authenticated user only when it's activated and
4. Lms/cms update edunext name into help-sidebar.

How to test
Be sure you have eox-tenant and eox-theming in your environment.

Clone the repo in env/build/openedx/themes and be sure to use the current branch dcoa/redwood-support

Add this line in env/build/openedx/settings/lms/assets.py and env/build/openedx/settings/cms/assets.py

COMPREHENSIVE_THEME_DIRS.extend(['/openedx/themes/ednx-saas-themes/edx-platform'])

In the lms.env.yml and cms.env.yml be sure to add:

USE_EOX_TENANT: True
DEFAULT_SITE_THEME: "bragi"
COMPREHENSIVE_THEME_DIRS: ["/openedx/themes/ednx-saas-themes/edx-platform"]

Open bash and compile bragi theme, context
source .tvm/bin/activate
tutor dev run lms bash

# Inside the lms bash 
openedx-assets themes --theme-dirs /openedx/themes/ednx-saas-themes/edx-platform --themes bragi

Now you'll see the default bragi theme applied in all LMS and any error about mako templates. Be sure you don't have selected any bragi-children in the THEME_OPTIONS in the tenant configs

https://edunext.atlassian.net/browse/DS-920

[bra-i-am]

LGTM!

[MaferMazu]

Looks good to me!