Standardize documentation for ReadtheDocs (#1027)

[ROCm/rccl commit: 246dbd16d7]

projects/rccl/.gitignore

@@ -1,13 +1,3 @@
 # Copyright (c) 2015-2016, NVIDIA CORPORATION. All rights reserved.
 *.gcov
 /coverage/
-
-# documentation artifacts
-build/
-_build/
-_images/
-_static/
-_templates/
-_toc.yml
-docBin/
-_doxygen/