sphinx documentation; adjusted all docstrings; moved some modules to non-public subpackage

setup.cfg

@@ -1,6 +1,6 @@
 [metadata]
 name = asyncio-taskpool
-version = 0.8.0
+version = 1.0.0-beta
 author = Daniil Fajnberg
 author_email = mail@daniil.fajnberg.de
 description = Dynamically manage pools of asyncio tasks
@@ -11,7 +11,7 @@ url = https://git.fajnberg.de/daniil/asyncio-taskpool
 project_urls =
     Bug Tracker = https://github.com/daniil-berg/asyncio-taskpool/issues
 classifiers =
-    Development Status :: 3 - Alpha
+    Development Status :: 4 - Beta
     Programming Language :: Python :: 3
     Operating System :: OS Independent
     License :: OSI Approved :: GNU Lesser General Public License v3 (LGPLv3)
@@ -30,6 +30,8 @@ python_requires = >=3.8
 [options.extras_require]
 dev =
     coverage
+    sphinx
+    sphinx-rtd-theme
 
 [options.packages.find]
 where = src