[WAL-8345] Remove brand label color settings and override options

Author: bugblasterX

README.md

@@ -280,7 +280,6 @@ You can see the list of all whitelabeling options below.
 - short_page_title
 - full_page_title
 - brand_color
-- brand_label_color
 - hero_link_label
 - hero_link_url
 - site_description

config/waldur-mastermind/whitelabeling.yaml

@@ -6,7 +6,6 @@
 #short_page_title: "changeme"
 #full_page_title: "Waldur | Cloud Service Management"
 #brand_color: "#307300"
-#brand_label_color: ""
 #hero_link_label: "changeme"
 #hero_link_url: "http://example.com"
 #site_description: "changeme"