docs/config: Group router docs together
docs/config: Group router docs together

So that it's easier to see what settings are common to many routers and we
don't duplicate descriptions.

guilhermebr/tsuru,cezarsa/tsuru,ggarnier/tsuru,gwmoura/tsuru,ggarnier/tsuru,mderaldo/tsuru,tuxmonteiro/tsuru,hcxiong/tsuru,4eek/tsuru,firebitsbr/tsuru,tuxmonteiro/tsuru,ArxdSilva/tsuru,kgrvamsi/tsuru,cezarsa/tsuru,cezarsa/tsuru,hcxiong/tsuru,ggarnier/tsuru,kgrvamsi/tsuru,jblancett/tsuru,gwmoura/tsuru,gwmoura/tsuru,RichardKnop/tsuru,cezarsa/tsuru,tuxmonteiro/tsuru,ArxdSilva/tsuru,cgvarela/tsuru,Endika/tsuru,ggarnier/tsuru,kgrvamsi/tsuru,hcxiong/tsuru,mderaldo/tsuru,Endika/tsuru,guilhermebr/tsuru,jblancett/tsuru,Endika/tsuru,gciotta/tsuru,guilhermebr/tsuru,ArxdSilva/tsuru,RichardKnop/tsuru,guilhermebr/tsuru,ArxdSilva/tsuru,cgvarela/tsuru,4eek/tsuru,gciotta/tsuru,RichardKnop/tsuru,jblancett/tsuru,mderaldo/tsuru,4eek/tsuru,firebitsbr/tsuru,tsuru/tsuru,tsuru/tsuru,firebitsbr/tsuru,gciotta/tsuru,cgvarela/tsuru,tsuru/tsuru,tsuru/tsuru