docs: link faq.rst in index.rst
docs: link faq.rst in index.rst

rc/sfepy,vlukes/sfepy,sfepy/sfepy,sfepy/sfepy,BubuLK/sfepy,vlukes/sfepy,rc/sfepy,vlukes/sfepy,sfepy/sfepy,BubuLK/sfepy,BubuLK/sfepy,rc/sfepy