enable to decide what digest method should be used to sign metadata

related circle, federation, federation export metadata;
added two columns (digest, digestexport) into federation and one column (digest) into provider entity model;
you can define default digest in config_rr.php
$config['signdigest'] = 'SHA-1'  or $config['signdigest'] = 'SHA-256'
if not found then default is set to  SHA-1
You can override default setting for federation (standard and export metadat)
ths information is passed by gearman client to gearman job server - see example gearman worker on  https://github.com/janul/rr3-addons/blob/master/gearman-workers/gearman-worker-metasigner.py
Also digest is passed to the list  https://SRV/jagger/sync_metadata/metadataslist  if you use cron scripts
Obviously it's stil up to metadata signer tool what digest is used but based on provided information yo can customize your tool more easily givin mor controlr to federation/providers operators

after update you need to rerun doctrine-cli to update db and regenerate model/proxies