Add cncf logo to cncf module docs.
-### The tremor language CNCF library.
+### <p align=center>
+### <img src="https://raw.githubusercontent.com/cncf/artwork/master/other/cncf/horizontal/color/cncf-color.png" width='35%'>
+### </p>
+###
+### <hr/>
+###
+### # The Tremor language CNCF library.
###
### It provides the following modules for cloud native computing:
###
