Fix wording in doc/install/Installation.md
Created by: slottermoser
Just a small typo fix. Change "## Add domains to list to the list of known hosts" to "## Add domains to the list of known hosts".
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Created by: slottermoser
Just a small typo fix. Change "## Add domains to list to the list of known hosts" to "## Add domains to the list of known hosts".