More dynamic local-storage-provisioner approach (#3472)

* Makes local volume provisioner more dynamic

* Correct variable name in local storage provisioner defaults

* Updates external-provisioner readme

* Updates variable naming to be more clear, more documentation, fixes sample inventory

* Variable refactor, untangled some jinja2 loops

* Corrects variable name

* No variable substitution in dict keys, replaced with anchor

* Fixes default storage_classes dict, inline docs

* Fixes spelling in inline docs

* Addresses comments in review

* Updates all the defaults

* Fix failing CI task

* Fixes external provisioner daemonset

roles/kubernetes-apps/external_provisioner/local_volume_provisioner/README.md

@@ -1,11 +1,51 @@
 Local Storage Provisioner
 =========================
 
-The local storage provisioner is NOT a dynamic storage provisioner as you would
+The [local storage provisioner](https://github.com/kubernetes-incubator/external-storage/tree/master/local-volume)
+is NOT a dynamic storage provisioner as you would
 expect from a cloud provider. Instead, it simply creates PersistentVolumes for
-all manually created volumes located in the directories specified in the `local_volume_provisioner_storage_classes.host_dir` entries.
-The default path is /mnt/disks and the rest of this doc will use that path as
-an example.
+all mounts under the host_dir of the specified storage class.
+These storage classes are specified in the `local_volume_provisioner_storage_classes` list.
+An example this list:
+
+```yaml
+local_volume_provisioner_storage_classes:
+  - local-storage:
+      host_dir: /mnt/disks
+      mount_dir: /mnt/disks
+  - fast-disks:
+      host_dir: /mnt/fast-disks
+      mount_dir: /mnt/fast-disks
+      block_cleaner_command:
+         - "/scripts/shred.sh"
+         - "2"
+      volume_mode: Filesystem
+      fs_type: ext4
+```
+
+For each dictionary in `local_volume_provisioner_storage_classes` a storageClass with the
+same name is created. The keys of this dictionary are converted to camelCase and added
+as attributes to the storageClass.
+The result of the above example is:
+
+```yaml
+data:
+  storageClassMap: |
+    local-storage:
+       hostDir: /mnt/disks
+       mountDir: /mnt/disks
+    fast-disks:
+       hostDir: /mnt/fast-disks
+       mountDir:  /mnt/fast-disks
+       blockCleanerCommand:
+         - "/scripts/shred.sh"
+         - "2"
+       volumeMode: Filesystem
+       fsType: ext4
+```
+
+The default StorageClass is local-storage on /mnt/disks,
+the rest of this doc will use that path as an example.
 
 Examples to create local storage volumes
 ----------------------------------------