Improve LibreSign sidebar

[Extarys]

This is a placeholder for tomorrow. As suggested in #4160 (comment)

Is your feature request related to a problem? Please describe.
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Describe the solution you'd like
The sidebar should contain everything related to LibreSign and that document.

I'll refer to a group signature when 1 or more parties need to sign a specific document "at the same time" for that document to be marked as fully signed by all parties. 1 person needs to sign: group signature, 10 people need to sign the document: group signature.

• All the group signatures completed:
  • Who requested it and when
  • Who signed it, when and how
  • Open/download the signed document
  • Delete the signed document if allowed (admin setting?)
• All the group signatures not yet completed (all of the above +:)
  • Who needs to sign it
    • Actions:
      • Resend signature request
        • Possible: By email + If instance account (or federated account): Send request by chat with Talk
      • Remove signature request

EDIT:
I forgot the main action: Ask for signature 😂

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
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[vitormattos]

Wow! Excellent!

Did you know Penpot?
Is an excelent open source web-based design tool that could help a lot to prototype new UI.
Exists a Nextcloud components library made to Penpot that could be used to prototype components.
Will be very good to have this made at Penpot.

Some points that are important to think about:

• Yes, we need the action to add a new signer (the current feature)
  This don't will be visible at signed documents, only will be visible at original document (or, maybe, we can put at signed document if the original document exists.
• Would be good to have an action to delete the sign request. This can open a Dialog and inside the dialog we can ask if also wish to delete the document, like the follow example that already exists when we try to delete a file at LibreSign file list:
  
• Would be good to have an action to delete the file. After click, we can open a confirm dialog to prevent acidental click at delete component.
• Actions menu at each signer. The follow actions only is visible when make sense to exists.
  
  • Need to add action to send a reminder (notification) to a signer (now stay at right side). Only is visible when the signer isn't herself.
  • Need to add the "delete" action to remove a signer from signers list (now stay at right side)

The status icon at left side of avatar isn't common at Nextcloud UI. Maybe would be good to move to right side or to another place, maybe together to tag of kind of sign request (email and account for now).