Basic layout for displaying "resources currently in lesson"

[AllanOXDi]

Summary

This PR implements the "shopping cart" preview functionality as part of aligning the lesson management workflow with the side panel management

References

#12787

Reviewer guidance

For now test if

• It displays an array of contentnodes, all of which are resources (no folders)

• In the bottom bar a link should be displayed whenever the array length is > 0

• On "select" it opens "shopping cart"

• The header should display the number of items in the selection array

• The lesson name is rendered in

• The "back" arrow "minimizes" the shopping cart view. The "X" closes the side panel. no validation for closing is required

• If each resource in the array is displayed as an item

• If each item should have a content node icon

Not working.
Displaying the file size for each item in the list.

Testing checklist

• Contributor has fully tested the PR manually
• If there are any front-end changes, before/after screenshots are included
• Critical user journeys are covered by Gherkin stories
• Critical and brittle code paths are covered by unit tests

PR process

• PR has the correct target branch and milestone
• PR has 'needs review' or 'work-in-progress' label
• If PR is ready for review, a reviewer has been added. (Don't use 'Assignees')
• If this is an important user-facing change, PR or related issue has a 'changelog' label
• If this includes an internal dependency change, a link to the diff is provided

Reviewer checklist

• PR is fully functional
• PR has been tested for accessibility regressions
• External dependency files were updated if necessary (yarn and pip)
• Documentation is updated
• Contributor is in AUTHORS.md

[github-actions]

Build Artifacts

Asset type	Download link
PEX file	kolibri-0.18.0a0.dev0_git.7.ged3453b2.pex
Windows Installer (EXE)	kolibri-0.18.0a0.dev0+git.7.ged3453b2-windows-setup-unsigned.exe
Debian Package	kolibri_0.18.0a0.dev0+git.7.ged3453b2-0ubuntu1_all.deb
Mac Installer (DMG)	kolibri-0.18.0a0.dev0+git.7.ged3453b2.dmg
Android Package (APK)	kolibri-0.18.0a0.dev0+git.7.ged3453b2-0.1.4-debug.apk
TAR file	kolibri-0.18.0a0.dev0+git.7.ged3453b2.tar.gz
WHL file	kolibri-0.18.0a0.dev0+git.7.ged3453b2-py2.py3-none-any.whl

[AllanOXDi]

hey @nucleogenesis this is the first part of the layout for displaying "resources currently in lesson. I have left few requirements out will get back to it on monday