[docs] add Apache license and source repository links to the home page
Welcome to the Font Bakery Documentation!
=========================================
-Font Bakery is a command-line tool for checking the quality of font projects.
+Font Bakery is command-line tool for checking the quality of font projects.
+
+The project is licensed under the `Apache v2.0 license <https://github.com/googlefonts/fontbakery/blob/master/LICENSE.txt>`_ and the source is available at https://github.com/googlefonts/fontbakery.
.. toctree::
:maxdepth: 2
