Switch from badSignatureAlgorithms to goodSignatureAlgorithms (#2989)
Switch from badSignatureAlgorithms to goodSignatureAlgorithms (#2989)

In ca/certificate-authority.go, we previously had a block list of signature algorithms we will not accept for CSRs. This commit switches to an allowed list of signature algorithms that we will accept.
jfrazelle/boulder,jcjones/boulder,lucasallan/boulder,jfrazelle/boulder,jcjones/boulder,lucasallan/boulder,letsencrypt/boulder,jsha/boulder,bmw/boulder,jsha/boulder,letsencrypt/boulder,jcjones/boulder,jsha/boulder,bmw/boulder,jfrazelle/boulder,ibukanov/boulder,jfrazelle/boulder,ibukanov/boulder,letsencrypt/boulder,lucasallan/boulder,ibukanov/boulder,bmw/boulder,jcjones/boulder