Add requirements for docs

Signed-off-by: Michal Čihař <michal@cihar.com>
Whitespace cleanup

Signed-off-by: Michal Čihař <michal@cihar.com>
Use sphinxcontrib.httpdomain for documenting API

Signed-off-by: Michal Čihař <michal@cihar.com>
Correctly cross reference hooks

Signed-off-by: Michal Čihař <michal@cihar.com>