Move README.profile.rst to docs/

Keep all documentation except the main README in the docs directory.

README.rst

@@ -35,7 +35,7 @@ custom live media, **releng** is used to create the monthly installation medium.
 They can be found below `configs/baseline/ <configs/baseline/>`_  and `configs/releng/ <configs/releng/>`_
 (respectively). Both profiles are defined by files to be placed into overlays (e.g. airootfs ‎→‎ the image's ``/``).
 
-Read `README.profile.rst <README.profile.rst>`_ to learn more about how to create profiles.
+Read `README.profile.rst <docs/README.profile.rst>`_ to learn more about how to create profiles.
 
 Create images
 =============