Adds initial doc rst files and configs.

.gitignore

docs/Makefile

docs/config

docs/source/conf.py

docs/source/index.rst

docs/source/library/capi/capi.rst

docs/source/library/capi/index.rst

docs/source/library/index.rst

docs/source/library/io/base.rst

docs/source/library/io/cassini_driver.rst

docs/source/library/io/index.rst

docs/source/library/io/io.rst

docs/source/library/io/lro_driver.rst

docs/source/library/io/mdis_driver.rst

docs/source/library/io/mro_driver.rst