Specify package requirements in docs folder

Specify requirements in etc and docs to work around RTD issue

Change-Id: Ia7889fa335e045eae22d17e7a090deaf1e95584a
Issue-ID: DOC-100
Signed-off-by: Rich Bennett <rb2745@att.com>
diff --git a/docs/requirements.txt b/docs/requirements.txt
new file mode 100644
index 0000000..35f9168
--- /dev/null
+++ b/docs/requirements.txt
@@ -0,0 +1,12 @@
+tox
+Sphinx==1.5.3
+doc8
+docutils
+setuptools
+six
+sphinxcontrib-httpdomain
+sphinxcontrib-blockdiag
+sphinxcontrib-seqdiag
+sphinxcontrib-swaggerdoc
+sphinxcontrib-plantuml
+sphinx_bootstrap_theme>=0.4.11