ci: speed up code-coverage jobs

Plus some documentation updates

Change-Id: I6fd2b04e22bca6c3d6e36e78d1995220e261206b
Refs: #3809
diff --git a/docs/conf.py b/docs/conf.py
index d0d0818..dbcdd3b 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -274,4 +274,4 @@
 
 # exclude_patterns = ['RELEASE_NOTES.rst']
 
-redmine_project_url = "http://redmine.named-data.net/"
+redmine_project_url = "https://redmine.named-data.net/"