Page to update:
https://documentation.magnolia-cms.com/display/DOCS57/Release+notes+for+Magnolia+CORE+5.7.3
Based on the following dev tickets:
https://jira.magnolia-cms.com/browse/MAGNOLIA-7511
https://jira.magnolia-cms.com/browse/MAGNOLIA-7492
https://jira.magnolia-cms.com/browse/MAGNOLIA-7491