Edited the readme and reorganized the toc (#69)

* Edited the readme so that it doesn't duplicate information in the official online docs

* rearranged the toc to match the new structure

* moved Docker section

[ROCm/rocjpeg commit: b2973fe98b]

projects/rocjpeg/docs/sphinx/_toc.yml.in

@@ -24,6 +24,12 @@ subtrees:
   - file: how-to/rocjpeg-decoding-a-jpeg-stream.rst
     title: Decoding a JPEG stream with rocJPEG
 
+- caption: Samples
+  entries:
+  - url: https://github.com/ROCm/rocJPEG/tree/develop/samples
+    title: rocJPEG samples on GitHub
+
+    
 - caption: Reference
   entries:
   - file: reference/rocjpeg-formats-and-architectures.rst
@@ -35,11 +41,6 @@ subtrees:
   - file: doxygen/html/annotated
     title: rocJPEG data structures
 
-- caption: Samples
-  entries:
-  - url: https://github.com/ROCm/rocJPEG/tree/develop/samples
-    title: rocJPEG samples on GitHub
-
 - caption: About
   entries:
   - file: license.md