Users can bookmark individual resources

[marcellamaki]

Within the updated content renderer, a user should be able to click on the bookmark icon to add or remove a bookmark, or access it through an option in the dropdown menu on a smaller screen.

Core functionality
Saving to bookmarks (filled in icon indicates resource is now bookmarked)

Removing from bookmarks (outline icon indicates resources is not bookmarked)

Bookmarks Figma Design File

To access the newly updated content renderer component in develop, you can review the following PR for instructions:
#8151

To review the newly added API Endpoint for bookmarks, you can review the PR that created it:
#8095

For more details on the Resource Layer, you can see this updated docs file:
https://github.com/learningequality/kolibri/blob/4c4a308231237013c07a08fe92277519da21710a/docs/dataflow/index.rst

Gherkin Scenarios (ALL)

Please see below for specific scenarios for this issue

Feature: Learners can bookmark resources and topics

	Scenario: Learners can bookmark resources in the Learn tab
		Given that I am on the Learn plugin
			And I navigate to a resource in the channels tab
		When I click bookmark icon on the resource card
		Then I see a snackbar confirming the resource was bookmarked
			And the resource is added to my list of bookmarks

	Scenario: Leanrers can bookmark topics in the Learn tab
		Given that I am on the Learn plugin
			And I navigate to a topic in the channels tab
		When I click bookmark icon near the topic title
		Then I see a snackbar confirming the topic was bookmarked
			And the topic is added to my list of bookmarks

Feature: Coaches can bookmark resources and topics

	Scenario: Coaches can bookmark resources while in the Learn Tab
		Given that I am on the Learn plugin
			And I navigate to a resource
		When I click bookmark icon on the resource card
		Then I see a snackbar confirming the resource was bookmarked
			And the resource is added to my list of bookmarks

	Scenario: Coaches can bookmark topics while in the Learn Tab
		Given that I am on the Learn plugin
			And I navigate to a topic
		When I click bookmark icon near the topic title
		Then I see a snackbar confirming the topic was bookmarked
			And the topic is added to my list of bookmarks