update module docs and sphinx config

doc/index.md

@@ -1,29 +1,37 @@
 # `trainlib` package docs 
+
 {ref}`genindex`
 {ref}`modindex`
-{ref}`search`
 
 ```{eval-rst}
 .. autosummary::
    :nosignatures:
+   :recursive:
+   :caption: Modules
 
-    # list modules here for quick links
+    trainlib.dataset
+    trainlib.domain
+    trainlib.estimator
+    trainlib.trainer
+    trainlib.transform
 ```
 
 ```{toctree}
 :maxdepth: 3
 :caption: Autoref
+:hidden:
 
-_autoref/index.rst
+_autoref/trainlib.rst
 ```
 
 ```{toctree}
 :maxdepth: 3
 :caption: Contents
+:hidden:
 
 reference/documentation/index
-reference/site/index
 ```
 
 ```{include} ../README.md
+:heading-offset: 1
 ```