Add rough draft for page and section bundles

- Also a table showing the main differences between page and section bundles on
  in Bundles section content.
- Minor update of description in front-matter.
- Update default `list.html` layout as a quick-fix for the issue explained in
  https://github.com/gohugoio/hugoDocs/issues/308#issuecomment-360235461

content/content-management/bundles/_index.md

@@ -2,11 +2,11 @@
 title : "Bundles"
 description : "Content organization using Bundles"
 date : 2018-01-24T13:09:00-05:00
-lastmod : 2018-01-24T13:27:22-05:00
+lastmod : 2018-01-25T16:35:56-05:00
+linktitle : "Bundles"
 categories : ["content management", "bundles"]
 draft : false
 toc : true
-linktitle : "Bundles"
 menu :
   docs:
     identifier : "bundles"
@@ -14,4 +14,7 @@ menu :
     weight : 9
 ---
 
-Content in "Bundles" branch.
+| Bundle type | Index file name                                                          |
+|-------------|--------------------------------------------------------------------------|
+| Page        | `index.md` or `index.html` or any `index.*` file with valid MIME type    |
+| Section     | `_index.md` or `_index.html` or any `_index.*` file with valid MIME type |

content/content-management/bundles/image-processing/index.md

@@ -1,13 +1,13 @@
 ---
 title : "Image Processing"
-description : "Hugo API for processing images that are part of page, section or branch bundles"
+description : "Hugo API for processing images that are part of page or section bundles"
 date : 2018-01-24T13:10:00-05:00
-lastmod : 2018-01-24T13:45:08-05:00
+lastmod : 2018-01-25T15:59:07-05:00
+linktitle : "Image Processing"
 categories : ["content management", "bundles"]
 weight : 4004
 draft : false
 toc : true
-linktitle : "Image Processing"
 ---
 
 Image processing is available on Page Resources. 

content/content-management/bundles/page-bundles/index.md

@@ -1,13 +1,58 @@
 ---
 title : "Page Bundles"
 description : "Organization of individual pages as bundles"
-date : 2018-01-24T13:10:00-05:00
-lastmod : 2018-01-24T13:45:07-05:00
+lastmod : 2018-01-25T16:38:34-05:00
+linktitle : "Page Bundles"
+keywords : ["page", "bundles"]
 categories : ["content management", "bundles"]
 weight : 4001
 draft : false
 toc : true
-linktitle : "Page Bundles"
 ---
 
-Content in "Page Bundles"
+A _Page Bundle_ is any directory at any hierarchy within the
+`content/` directory, that contains at least an `index.md` file (**not
+`_index.md`**).
+
+{{% note %}}
+Here `md` (markdown) is used just as an example. You can use any file
+type as a content resource as long as it is a MIME type recognized by
+Hugo (`json` files will, as one example, work fine). If you want to
+get exotic, you can define your own media type.
+{{% /note %}}
+
+
+## Examples of Page Bundle organization {#examples-of-page-bundle-organization}
+
+```text
+content/
+├── page-bundle-1
+│   ├── content1.md
+│   ├── content2.md
+│   ├── image1.jpg
+│   ├── image2.png
+│   └── index.md
+└── some-section
+    ├── ..
+    ├── ..
+    └── page-bundle-2
+        └── index.md
+```
+
+In the above example `content/` directory, there are two page bundles:
+
+`page-bundle-1`
+: This page bundle has the `index.md`, two other
+    content Markdown files and two image files.
+
+`page-bundle-2`
+: This page bundle is nested in a section. This
+    bundle has only the `index.md`.
+
+{{% note %}}
+The hierarchy depth at which a page bundle is created does not matter,
+as long as it's not inside another **page** bundle.
+{{% /note %}}
+
+
+## <span class="todo TODO_">TODO </span> Headless Page Bundle {#headless-page-bundle}

content/content-management/bundles/section-bundles/index.md

@@ -1,13 +1,56 @@
 ---
 title : "Section Bundles"
-description : "Organization of sections and branches as bundles"
-date : 2018-01-24T13:10:00-05:00
-lastmod : 2018-01-24T13:45:07-05:00
+description : "Organization of sections as bundles"
+lastmod : 2018-01-25T16:39:52-05:00
+linktitle : "Section Bundles"
+keywords : ["section", "bundles"]
 categories : ["content management", "bundles"]
 weight : 4002
 draft : false
 toc : true
-linktitle : "Section Bundles"
 ---
 
-Content in "Section Bundles"
+A _Section Bundle_ is any directory at any hierarchy within the
+`content/` directory, that contains at least an `_index.md` file (**not
+`index.md`**). This `_index.md` can also be directly under the
+`content/` directory.
+
+{{% note %}}
+Here `md` (markdown) is used just as an example. You can use any file
+type as a content resource as long as it is a MIME type recognized by
+Hugo (`json` files will, as one example, work fine). If you want to
+get exotic, you can define your own media type.
+{{% /note %}}
+
+
+## Examples of Section Bundle organization {#examples-of-section-bundle-organization}
+
+```text
+content/
+├── section-bundle-1
+│   ├── section-content1.md
+│   ├── section-content2.md
+│   ├── image1.jpg
+│   ├── image2.png
+│   └── _index.md
+└── section-bundle-2
+    ├── _index.md
+    └── page-bundle-1
+        └── index.md
+```
+
+In the above example `content/` directory, there are two section
+bundles (and a page bundle):
+
+`section-bundle-1`
+: This section bundle has the `_index.md`, two
+    other content Markdown files and two image files.
+
+`section-bundle-2`
+: This section bundle has the `_index.md` and a
+    nested page bundle.
+
+{{% note %}}
+The hierarchy depth at which a section bundle is created does not matter,
+as long as it's not inside another **section** bundle.
+{{% /note %}}

themes/gohugoioTheme/layouts/_default/list.html

@@ -1,4 +1,4 @@
 {{ define "main" }}
-  {{ $section_to_display :=  .Sections | default .Paginator.Pages }}
+  {{ $section_to_display :=  .Sections | union .Paginator.Pages }}
   {{ partial "pagelayout.html" (dict "context" . "section_to_display" $section_to_display ) }}
 {{ end }}