collector: read provisioner from config
collector: read provisioner from config

Also register juju provisioner by importing it

Related to #211.

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