Update XSS policy to allow iframe and link with custom protocol
Update XSS policy to allow iframe and link with custom protocol

xnum/hackmd,Rwing/hackmd,ironhack/hackmd,PeterDaveHello/hackmd,jccrofty30/hackmd,Rwing/hackmd,PeterDaveHello/hackmd,aswathyjacob8/newtest,aswathyjacob8/newtest,jccrofty30/hackmd,hackmdio/hackmd,xnum/hackmd,jackycute/HackMD,xnum/hackmd,ironhack/hackmd,Yukaii/hackmd,PeterDaveHello/hackmd,jackycute/HackMD,Yukaii/hackmd,ironhack/hackmd,Rwing/hackmd,hackmdio/hackmd,jackycute/HackMD,hackmdio/hackmd,Yukaii/hackmd,jccrofty30/hackmd,aswathyjacob8/newtest