Add link to list of data dictionaries

[janette]

• Updates the 'Data Dictionary' menu item to take user to a data dictionary view
• Title links in the data dictionary view send you to the API endpoint
• The default dataset content view alter code updated to check if the dkan_js_frontend module is enabled. If yes, titles link to the react dataset page. If no, titles link to the Drupal node route.

QA Steps

• Checkout this branch
• ddev drush en sample-content dkan_js_frontend -y
• ddev dkan-frontend-install
• ddev dkan-frontend-build
• ddev drush dkan:sample-content:create
• ddev drush cron
• ddev drush uli
• Use the DKAN menu, click on "Data Dictionary"
• Confirm you end up on a data dictionary view
• Confirm there is a button for adding a new data dictionary
• Create a data dictionary and return to the list view
• Click the title of the data dictionary
• Confirm you see the API endpoint for the data dictionary
• Visit /admin/dkan/datasets
• Confirm title links take you to the react dataset page
• ddev drush pmu dkan_js_frontend -y
• ddev drush cr
• Visit /admin/dkan/datasets
• Confirm the title links take you to the /node/nid page

[dafeder]

Looks great - one note, I think submitting a data dictionary needs to redirect to the list, not back to the dataset list. But we can address that in a future PR.