Add Documentation (#125)

Add sphinx docs with readthedocs integration.

Docs can be built locally with `poe docs`.

docs/conf.py

@@ -0,0 +1,60 @@
+# Configuration file for the Sphinx documentation builder.
+#
+# This file only contains a selection of the most common options. For a full
+# list see the documentation:
+# https://www.sphinx-doc.org/en/master/usage/configuration.html
+
+# If extensions (or modules to document with autodoc) are in another directory,
+# add these directories to sys.path here. If the directory is relative to the
+# documentation root, use os.path.abspath to make it absolute, like shown here.
+
+import pathlib
+
+import toml
+
+
+# -- Project information -----------------------------------------------------
+
+project = "betterproto"
+copyright = "2019 Daniel G. Taylor"
+author = "danielgtaylor"
+pyproject = toml.load(open(pathlib.Path(__file__).parent.parent / "pyproject.toml"))
+
+
+# The full version, including alpha/beta/rc tags.
+release = pyproject["tool"]["poetry"]["version"]
+
+
+# -- General configuration ---------------------------------------------------
+
+# Add any Sphinx extension module names here, as strings. They can be
+# extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
+# ones.
+extensions = [
+    "sphinx.ext.autodoc",
+    "sphinx.ext.intersphinx",
+    "sphinx.ext.napoleon",
+]
+
+autodoc_member_order = "bysource"
+autodoc_typehints = "none"
+
+extlinks = {
+    "issue": ("https://github.com/danielgtaylor/python-betterproto/issues/%s", "GH-"),
+}
+
+# Links used for cross-referencing stuff in other documentation
+intersphinx_mapping = {
+    "py": ("https://docs.python.org/3", None),
+}
+
+
+# -- Options for HTML output -------------------------------------------------
+
+# The name of the Pygments (syntax highlighting) style to use.
+pygments_style = "friendly"
+
+# The theme to use for HTML and HTML Help pages.  See the documentation for
+# a list of builtin themes.
+
+html_theme = "sphinx_rtd_theme"