Show required role for signing

In the signee list, when a role is expected to sign, it should be visible. `"Role: is expected to sign"`. In todays signature solutions, role based signature rules are defined in policy.xml. For dynamic signees as introduced with parallell and user defined signees in SingingV2, an interface is used to define the rules for signees.

How should required role signature be communicated? Should policy.xml be used for role based signee assignments in V2 as in V1?

Start by comparing the existing V1 role-based signature rules in policy.xml with the V2 dynamic-signee interface described in the issue. Trace how the signee list represents expected signees, then define whether V2 should use policy.xml and what visible required-role message constitutes completion.

Written by the indexing model from the issue text.