Add root docs directory
This change adds a docs directory at the root level of the Pigweed
repository for building documentation for the entirety of Pigweed.
The directory contains a top-level index.rst and conf.py for docgen,
and a pw_doc_gen build target to render the documentation.
Change-Id: Iba981c64662d48a1d23bb7bda9bf0ed5a104873b
diff --git a/docs/index.rst b/docs/index.rst
new file mode 100644
index 0000000..07829ba
--- /dev/null
+++ b/docs/index.rst
@@ -0,0 +1,15 @@
+=======
+Pigweed
+=======
+
+Pigweed is a collection of embedded-focused libraries, which we call "modules".
+These modules are designed for small-footprint MMU-less microcontrollers like
+the ST Micro STM32L452 or the Nordic NRF82832. The modules are designed to
+facilitate easy integration into existing codebases.
+
+.. toctree::
+ :maxdepth: 1
+ :hidden:
+
+ pw_bloat/bloat
+ pw_preprocessor/docs