Automatic merge from submit-queue (batch tested with PRs 41139, 41186, 38882, 37698, 42034)
create configmap from-env-file
Allow ConfigMaps to be created from Docker based env files.
See proposal https://github.com/kubernetes/community/issues/165
**Release-note:**
```release-note
1. create configmap has a new option --from-env-file that populates a configmap from file which follows a key=val format for each line.
2. create secret has a new option --from-env-file that populates a configmap from file which follows a key=val format for each line.
```