Added documentation to tempest-account-generator

Added docstring to cmd/account_generator.py.
Fixed help messages.
Added sphinx documentation for tempest-account-generator utility.

Change-Id: I6640ba8a0eaaea187cf38582ab537394dec020b6
diff --git a/doc/source/account_generator.rst b/doc/source/account_generator.rst
new file mode 100644
index 0000000..1c30473
--- /dev/null
+++ b/doc/source/account_generator.rst
@@ -0,0 +1,5 @@
+--------------------------------
+Tempest Test-Account Generator Utility
+--------------------------------
+
+.. automodule:: tempest.cmd.account_generator
\ No newline at end of file
diff --git a/doc/source/index.rst b/doc/source/index.rst
index cb1c504..f925018 100644
--- a/doc/source/index.rst
+++ b/doc/source/index.rst
@@ -45,6 +45,7 @@
 .. toctree::
    :maxdepth: 1
 
+   account_generator
    cleanup
    javelin