[sovereign] Send bitmap outgoing operations

[mariusmihaic]

Reasoning behind the pull request

• Send validators pub keys bitmap + epoch in outgoing operations

Proposed changes

• No signature is applied on the extra data. Bitmap + aggregated signature will be enough to verify data's validity

Testing procedure

Pre-requisites

Based on the Contributing Guidelines the PR author and the reviewers must check the following requirements are met:

• was the PR targeted to the correct branch?
• if this is a larger feature that probably needs more than one PR, is there a feat branch created?
• if this is a feat branch merging, do all satellite projects have a proper tag inside go.mod?