use https everywhere (#6574)

* use https everywhere

* use https links on the files that are left

Also, removed some broken links and updated redirections.

plugins/kube-ps1/kube-ps1.plugin.zsh

@@ -10,7 +10,7 @@
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
 #
-#     http://www.apache.org/licenses/LICENSE-2.0
+#     https://www.apache.org/licenses/LICENSE-2.0
 #
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,