Update authorization documentation
Update authorization documentation

* Add a section about an authorizer
* Update example to use `Authorizer<P>`
* Add a note about roles in the `Protecting Resources` section

Toilal/dropwizard,mnrasul/dropwizard,wilko55/dropwizard,jelgh/dropwizard,micsta/dropwizard,Toilal/dropwizard,vikasshinde22105/dropwizard,StanSvec/dropwizard,helt/dropwizard,vikasshinde22105/dropwizard,calou/dropwizard,chaminda204/dropwizard,chaminda204/dropwizard,ryankennedy/dropwizard,mulloymorrow/dropwizard,ryankennedy/dropwizard,jelgh/dropwizard,pradex/dropwizard,calou/dropwizard,tburch/dropwizard,phouse512/dropwizard,grange74/dropwizard,philandstuff/dropwizard,ben1247/dropwizard,svenefftinge/dropwizard,tjcutajar/dropwizard,xiaoping2367/dropwizard,bbrighttaer/dropwizard,takecy/dropwizard,wakandan/dropwizard,jplock/dropwizard,qinfchen/dropwizard,taltmann/dropwizard,rgupta-okta/dropwizard,tiankong1986/dropwizard,helt/dropwizard,akraxx/dropwizard,nickbabcock/dropwizard,cvent/dropwizard,Randgalt/dropwizard,wilko55/dropwizard,tiankong1986/dropwizard,wakandan/dropwizard,mosoft521/dropwizard,phouse512/dropwizard,phambryan/dropwizard,akshaymaniyar/dropwizard,zhiqinghuang/dropwizard,calou/dropwizard,svenefftinge/dropwizard,aaanders/dropwizard,mattnelson/dropwizard,dotCipher/dropwizard,mulloymorrow/dropwizard,ajaiyen/dropwizard,wakandan/dropwizard,StanSvec/dropwizard,anonymint/dropwizard,puneetjaiswal/dropwizard,akraxx/dropwizard,nmharsha93/dropwizard,flipsterkeshav/dropwizard,mattnelson/dropwizard,dropwizard/dropwizard,phambryan/dropwizard,akshaymaniyar/dropwizard,pkwarren/dropwizard,amillalen/dropwizard,wangcan2014/dropwizard,bbrighttaer/dropwizard,pradex/dropwizard,phambryan/dropwizard,amillalen/dropwizard,ben1247/dropwizard,ajaiyen/dropwizard,MikaelAmborn/dropwizard,nmharsha93/dropwizard,michelle-liang/dropwizard,aaanders/dropwizard,evnm/dropwizard,thomasandersen77/dropwizard,sridhar-newsdistill/dropwizard,christophercurrie/dropwizard,qinfchen/dropwizard,shawnsmith/dropwizard,ajaiyen/dropwizard,MikaelAmborn/dropwizard,Trundle/dropwizard,kjetilv/dropwizard,Alexey1Gavrilov/dropwizard,yshaojie/dropwizard,Alexey1Gavrilov/dropwizard,tburch/dropwizard,philandstuff/dropwizard,sridhar-newsdistill/dropwizard,phouse512/dropwizard,sytolk/dropwizard,jelgh/dropwizard,xiaoping2367/dropwizard,pradex/dropwizard,thomasandersen77/dropwizard,zhiqinghuang/dropwizard,vikasshinde22105/dropwizard,Randgalt/dropwizard,puneetjaiswal/dropwizard,dropwizard/dropwizard,cvent/dropwizard,ben1247/dropwizard,randiroe/dropwizard,wilko55/dropwizard,thomasandersen77/dropwizard,flipsterkeshav/dropwizard,biogerm/dropwizard,mulloymorrow/dropwizard,mnrasul/dropwizard,hbrahi1/dropwizard,taltmann/dropwizard,zhiqinghuang/dropwizard,vforce/dropwizard,nmharsha93/dropwizard,douzzi/dropwizard,mosoft521/dropwizard,mtbigham/dropwizard,rgupta-okta/dropwizard,douzzi/dropwizard,patrox/dropwizard,kjetilv/dropwizard,sridhar-newsdistill/dropwizard,svenefftinge/dropwizard,dotCipher/dropwizard,pkwarren/dropwizard,mnrasul/dropwizard,taohaolong/dropwizard,takecy/dropwizard,amillalen/dropwizard,wangcan2014/dropwizard,xiaoping2367/dropwizard,vforce/dropwizard,MikaelAmborn/dropwizard,dotCipher/dropwizard,sytolk/dropwizard,nickbabcock/dropwizard,wangcan2014/dropwizard,pkwarren/dropwizard,grange74/dropwizard,helt/dropwizard,grange74/dropwizard,akraxx/dropwizard,mattnelson/dropwizard,tjcutajar/dropwizard,sytolk/dropwizard,taohaolong/dropwizard,taohaolong/dropwizard,yshaojie/dropwizard,arunsingh/dropwizard,michelle-liang/dropwizard,tiankong1986/dropwizard,takecy/dropwizard,Toilal/dropwizard,hbrahi1/dropwizard,arunsingh/dropwizard,kdave47/dropwizard,jplock/dropwizard,mtbigham/dropwizard,micsta/dropwizard,randiroe/dropwizard,biogerm/dropwizard,christophercurrie/dropwizard,puneetjaiswal/dropwizard,hbrahi1/dropwizard,arunsingh/dropwizard,Trundle/dropwizard,patrox/dropwizard,yshaojie/dropwizard,ryankennedy/dropwizard,Alexey1Gavrilov/dropwizard,christophercurrie/dropwizard,vforce/dropwizard,nickbabcock/dropwizard,randiroe/dropwizard,taltmann/dropwizard,biogerm/dropwizard,cvent/dropwizard,qinfchen/dropwizard,StanSvec/dropwizard,michelle-liang/dropwizard,tburch/dropwizard,mtbigham/dropwizard,kdave47/dropwizard,mosoft521/dropwizard,Trundle/dropwizard,patrox/dropwizard,shawnsmith/dropwizard,flipsterkeshav/dropwizard,philandstuff/dropwizard,akshaymaniyar/dropwizard,shawnsmith/dropwizard,dropwizard/dropwizard,chaminda204/dropwizard,tjcutajar/dropwizard,anonymint/dropwizard,Randgalt/dropwizard,rgupta-okta/dropwizard,evnm/dropwizard,micsta/dropwizard,kdave47/dropwizard,aaanders/dropwizard,evnm/dropwizard,douzzi/dropwizard,jplock/dropwizard,kjetilv/dropwizard,bbrighttaer/dropwizard